The Fresh Loaf

A Community of Amateur Bakers and Artisan Bread Enthusiasts.

GUIDE : KitchenAid 5KSM7591 and 5KSM7990 Gearbox Disassembly [IMAGE HEAVY]

DanielCoffey's picture
DanielCoffey

GUIDE : KitchenAid 5KSM7591 and 5KSM7990 Gearbox Disassembly [IMAGE HEAVY]

GUIDE : KitchenAid Heavy Duty 5KSM7591 and 5KSM7990 Gearbox Disassembly

This is intended to be a helpful guide to disassembly, cleaning and re-greasing of the gearbox and planetary ring of the newer KitchenAid Heavy Duty Stand Mixers. It is specific to the following two models as they have a completely redesigned gearbox and motor.

MODEL : 5KSM7591 (all variants)
MODEL : 5KSM7990 (all variants)

The process for the US (120V) and EU (220-240V) models is exactly the same.

As is often the case when taking a machine to pieces for the first time, you only discover the most efficient method of doing to AFTER you have taken your pictures and put it back together and this is no exception. I started by removing one piece at a time and taking pictures as I did so. I effectively nibbled the machine to bits in a logical manner. Afterwards I realised that several groups of pieces would come off in one block and make the reassembly process simpler. I will try to outline these discoveries as they will appear different from some of the pictures taken.



For this guide I am assuming you have one the of the relevant KitchenAid models and have unplugged it from the wall completely. There are no visible large capacitors but always be aware that there may be residual charge associated with the motor power supply. Leaving the machine unplugged for half an hour should take care of this.


TOOLS REQUIRED

Medium crosshead screwdriver
Small flat-head screwdriver
Torx T15 screwdriver bit
Medium Circlip (C-clip) pliers
Small hammer
Small punch
Food Safe (1H) grease (only a modest amount is required)
Rubber gloves (disposable nitrile gloves are perfect for this)
Kitchen paper
Very hot soapy water and an old toothbrush


DISASSEMBLY - TOP COVER

As is usual for most of the KitchenAid Stand Mixers of this size, the top lid comes off to reveal the motor and gearbox. The screws to access the top lid are concealed behind the silver flexible band that runs round the machine.

There is a single screw at the back which will release the band. Take it off carefully and set aside.



This will reveal the four crosshead screws that secure the lid. There are two on each side.



Once the lid is off you can see the new design of the machine. The electrical control board is flat underneath the motor. The gearbox is inline with the motor and extends forward to the accessory socket. The planetary ring resides underneath via a 90-degree gear as usual.




Take particular note of the two cables that attach to the motor. We will have to remove those later in order to release the entire motor and gearbox assembly in one piece. One is a power connector with two wires that is locked together with a small tab. The other is a magnetic sensor on a black cable that fits into a slot at the back of the motor. It too is secured by a plastic tab but is fairly delicate.


DISASSEMBLY - PLANETARY RING

The first part to remove is the enamelled planetary ring to which you would attach the whisk, beater or dough hook. It is held in place with a single punch pin.



Taking care not to slip and mark the paint, tap the pin out from one side. Once it protrudes enough to remove, the complete enamelled planetary ring will slide down and off.



Turning it over will reveal a circlip (c-clip) which needs to be removed.



The best tool for the job is a pair of circlip pliers. The type that gape open when squeezed is better than the cheaper "squeeze to close" sort. Insert the two prongs of the circlip pliers into the eye holes of the clip, spread them just enough to clear the slot the clip is located in and remove it. The gear that is held captive will come off revealing that it has a slot on the underside.



You can see how the slot on the underside goes over a floating pin that passes through the planetary shaft.



Slide this pin out by hand and take off the spacer washer underneath. The planetary shaft will now drop out. I was surprised that in my specific stand mixer there was very little grease on the planetary shaft and it did show signs of wear. You do not need to remove the tool retaining cap, spring and circlips. A simple brushing should clean them enough.



Here are the small components in the order they belong.



Looking underneath the head of the mixer will reveal the large planetary ring gear.



Because I was not familiar with the disassembly of the machine in its sections I removed the four crosshead screws to release the large planetary ring gear. While there is no disadvantage in doing this, it is also released with a pair of reinforcing plates when the motor and gearbox is removed.



With the large ring gear removed you can see the underside of two reinforcing plates that provide extra strength to the motor and gearbox above. If you leave the large planetary ring in place, it drops free with those two curved reinforcing plates once the motor and gearbox are released.




DISASSEMBLY - MOTOR AND GEARBOX REMOVAL

Since I was "nibbling" my machine into its individual pieces I had not worked out at this point that the motor and gearbox came out easily in one piece. I had first separated the motor from the gearbox, discovered that the two cables to the motor needed removing to allow it to be lifted away and then took the gearbox into its component parts last.

The easiest way to take this to pieces is to remove the motor and gearbox in one piece then separate it into its individual pieces afterwards.

First disconnect the motor power cable. A small flat screwdriver can be used to press in the locking clip to allow the two sides to slide apart.



Next the magnetic rotation sensor has to be removed. It is the slim flat black cable attaching to the rear of the motor near the fan. I found the easiest way to release it was to press in on the locking tab while pressing upwards gently from underneath. I was not sure how strong the cable itself was to pulling so I chose to press up from underneath until the locking clip was passed. TAKE CARE here as the tip of that sensor is somewhat delicate. Lift it clear of the motor and to one side.



Now that both of the motor connections have been removed it is now possible to undo the eight screws that hold the entire motor and gearbox in place. Take note of the eight screws (four on each side) where the gearbox meets the enamelled frame of the mixer.




These eight screws go through the frame and into the pair of curved reinforcing brackets above the large planetary gear. Undoing these eight screws will release the motor and gearbox (which will want to tip down as the last screw is undone) as well as allow the large planetary gear to fall down freely.

EITHER remove the large planetary gear first and then catch the two curved brackets as they are released OR place a towel below the large planetary gear to catch it as it drops. It is not heavy.

Note that the two curved brackets have a flat side (bottom) and a side with studs (top). Both brackets are identical.


Once the last of the eight screws are removed the entire motor and gearbox will be released. Lift it all away in once piece, taking care not to let it drop onto the electronics board underneath as you remove it.

From this point on you will see that I split the motor from the gearbox when I disassembled my machine while taking the photos. The process from this point is exactly the same whether you leave the gearbox behind or take it all off with the motor in one piece.


DISASSEMBLY - MOTOR SEPARATION

Lay the motor and gearbox on a flat surface and remove the two long Torx T15 screws that hold the two sections together.

Slide the motor backwards slowly. You will probably find that the set of small gears at the back of the gearbox will want to fall backwards and come out with the motor. It may be more convenient to encourage them to stay forwards within the gearbox using a small flat screwdriver as you slide the motor backwards. Do not worry if any do fall out as there is only one way to put them back together afterwards.

If you manage to get all the gears to stay with the gearbox then the motor will be released revealing a short hexagonal shaft. Wipe this side of the motor clean of old grease with a dry piece of paper and set it aside. Take care not to disturb a thin rubber o-ring that goes between the motor and the back of the gearbox. In my case it was retained by a groove on the motor face.


DISASSEMBLY - GEARBOX COMPONENTS

It is now time to reveal the inner workings of the gearbox and get it clean. First use your Torx T15 screwdriver to remove the two short screws on the top gearbox cover. There is a thin fiber gasket attached to the back of the lid which should be handled carefully as it needs to be reused.



This will reveal the front accessory gear, the 90-degree planetary gear below that and a circular gearbox with two sets of small floating gears. Notice how little grease is used compared to the older models of KitchenAid. There is no large grease "reservoir" needed.



Gently slide the circular gearbox backwards and off the front housing. There is another delicate o-ring here and it is not guaranteed which of the two pieces it will stick to. In my case it stayed with the forward housing.




Once this circular gearbox is away then the front accessory shaft and its bushing can be slid backwards then up and away.




This just leaves the 90-degree planetary gear left in the housing.



Flip it over and note the large circlip on the underside. This needs to be removed with circlip pliers and it will then release a thin spacer and the 90-degree planetary gear.



Here are the parts grouped together.




CLEANING - ALL PARTS

All the gears, clips, spacers and housings are now ready for cleaning. Do not worry about the order or location of any small parts from the gearbox as they are easy to identify and only fit together correctly one way. I will examine the gearbox shortly so in the meantime all small parts can be cleaned and dried.

First remove any large blobs of old grease with the flat screwdriver and discard. Do not try to reuse any of the old grease as it will be dried and degraded.

Now boil a kettle and find an easily washable but shallow container that can hold about 2cm of water with a little extra room for splashing. Pour in some freshly boiled water and a generous squeeze of washing up liquid. It is beneficial to wear disposable gloves at this point as extremely hot water with strong detergent is very harsh on the hands.

DO NOT attempt to clean the motor with water. A simple wipe of the hexagonal shaft with a clean dry cloth is all that it needs.

Use the old toothbrush to scrub and clean each small part and housing until it is grease free. Rinse each part in cold water, shake dry and set aside on a paper towel to dry completely. You may find you need something like a small toothpick or cocktail stick to get into the central hole of the gears or places where a pin went through. You may need to change the hot water a couple of times. The old grease will melt and become suspended in the water only if it is very hot. Water that is not hot enough will simply result in the grease smearing over the part and brush.

Once all parts are clean and dry, it is time to examine the gearbox to understand how it works.


EXAMINATION - GEARBOX

Placing all the cleaned gearbox parts together it is possible to work out how rotation from the motor is geared down and transferred to the forward accessory shaft and also down to the planetary ring.

Here are the parts that run from the motor to the accessory shaft.



From right to left there is a small gear that sits on that hexagonal shaft of the motor. This small gear sits in the middle of three larger gears that sit on the three prongs of the central armature. Three more gears go in front of the armature and sit on the prongs of the accessory shaft. The whole assembly is surrounded by a toothed ring that holds it all together and helps with rotation and alignment.

You will have noticed that there are two sets of three gears that differ in thickness. The thinner ones belong at the rear (motor) side and the fatter ones belong at the front. All these sets of three gears are symmetrical so there is no front or rear to any individual gear.

So let's look at how these gears transfer power from the motor to the accessory and planetary shafts.

Firstly the motor itself engages with the smallest gear (12T). This has to rotate at the same speed as the motor. Next come the three larger gears (29T). These all turn the same way and slow down the speed. There are three of them to support the central gear evenly and reduce wear. They sit on the central armature.



By placing the armature inside the toothed ring, you now force the armature to turn in the same direction as the three gears.



Turning it round so you can see the front, it is apparent that the central armature has a small gear (12T) fixed to it. As the armature slowly turns, this fixed gear has to turn too.



Now the three fat gears (29T) are fitted and their job is to slow the rotation down even further. There are three of them again so that wear is evenly distributed and the central armature is supported properly.




Because it is hard to get the three gears lined up exactly (it is possible to be one tooth out in the outer ring and the assembly will lock rather than turn), it is better to use the forward accessory shaft to locate the three gears and only then bring them into the outer ring as a group. That way their alignment will be guaranteed to be correct.



For now set these gears aside until it is time to grease them but remember how they go together.


REASSEMBLY - GEARBOX AND MOTOR

Once I had completed taking my photos I realised that it would have been much more convenient to grease and build the gearbox and motor on the bench before trying to fit any parts back on the machine. I will describe the optimal steps to perform the greasing and reassembly but the pictures may differ from the description.

The first step is to fit the 90-degree planetary gear back into the front gearbox housing. In my specific machine there was no grease in the bearing of the housing and 90-degree planetary gear but I think there should have been. Apply a small amount of grease to the bearing where the 90-degree planetary gear will pass through the housing. Also lightly grease the "top" of the bearing where the 90-degree planetary gear will rest. Have a look at it before greasing anything and think about where two surfaces would touch and move. Only a light amount of grease is necessary here.

Pack the teeth of the 90-degree planetary gear with grease and lightly grease the underside of the gear where it rests on the floor of the housing. Drop it into place in the housing and secure it from underneath with its spacer and circlip. Make sure the circlip is correctly located into its groove.



Apply a very small amount of grease to the front of the accessory shaft where it passes through its bushing as well as the face where the two parts meet.



Pack the teeth of the accessory shaft with grease and place it back onto the housing. It will engage with the 90-degree planetary shaft as well as the front of the housing. The flat sides of the accessory shaft bushing should be oriented straight up and down to seat properly.



I tried to grease and build up the entire gearbox ring on one piece but quickly realised that the correct next step was to place the three fat gears onto the prongs of the accessory shaft as this will guarantee their correct spacing. Pack the teeth with grease. Also grease the prongs of the accessory shaft. Be somewhat generous with the grease but not excessive.



Now grease the small gear (12T), its three thin companion gears (29T), the central armature and the entirety of the inside of the circular gearbox housing. Again be somewhat generous but not excessive. Too much grease here will cause additional resistance for the motor and will just end up with the excess being forced forwards where it will not serve any purpose.



When placing the outer toothed ring over the armature, note that there is a step in the casing of the outer ring. The step goes forward towards the front housing and its flat face goes backwards towards the motor.

Making sure that the outer ring is facing the correct way, bring it in to the three fat gears resting on the front accessory shaft. It may take a little care to line up correctly but the three fat gears need to be engaged correctly with the teeth on the inside of the outer ring. Once correct they should slide nicely backwards until the small fixed gear (12T) on the central armature needs to fit in between the three fat gears. Do not use force. It should engage easily but be aware that the armature may want to slide backwards out of the ring.

This is the part where assembling the gearbox while it is off the stand mixer is much more convenient than trying to assemble it while the housing is attached to the frame.

Once it is all together correctly it should look like this. Note the amount of grease that you should be aiming for. Plenty but not too much.



It would now be appropriate to replace the gearbox top cover and its two Torx T15 screws. I do not have a picture of this stage.

Reconnect the motor to the back of the gearbox housing. The hexagonal motor shaft needs to locate inside the small central gear (12T). Use the two long Torx T15 screws to join the two sections. They should be snug but not excessively tight.




REASSEMBLY - PLANETARY

It is now time to reattach the complete motor and gearbox to the mixer. This is slightly awkward as the motor has to be supported so that it does not drop onto the circuit board at the same time as the two curved reinforcing plates are attached from underneath.

Four of the eight crosshead screws are necessary to attach the motor to the frame and the other four are used to secure the curved reinforcing plates. Counting from the front, the SECOND and FOURTH pairs of screws hold the motor and gearbox to the frame while the FIRST and THIRD pairs secure the two reinforcing plates.

Attach the gearbox and motor to the frame by fitting the SECOND and FOURTH pairs of screws. Do not tighten fully as we will slacken and retighten all the screws once all four pairs are fitted properly.

Next, hold each reinforcing plate in its place from underneath the planetary ring and fit the FIRST and THIRD pairs of screws. Both plates are the same. Once all four pairs of screws are fitted, slacken them slightly, make sure the gearbox housing is sitting straight then tighten all screws down properly.

Carefully reconnect the power and magnetic sensor cables to the motor until they snap into place and are held firmly. Be careful with the magnetic sensor.




We should now be back at this stage (ignore the presence of the enamelled planetary ring in this picture)...



Next, lightly grease the teeth of the large planetary gear. Do not use too much grease as there is not much load on this part of the machine.



Using the four small screws, fix the large planetary gear to the frame. Once all four are in place, loosen slightly, check the fit of the large planetary gear then retighten all four screws.



Very lightly grease the sides of the 90-degree planetary gear shaft.

Very lightly grease the sides of the shaft that goes through the enamelled planetary ring. Lightly grease the teeth of the small gear on the enamelled planetary ring and secure it correctly on the floating pin. Remember it has a notch on the underside that locates onto the floating pin. Secure it with its circlip.



Slide the enamelled planetary ring up onto the bottom of the 90-degree planetary shaft and hold it in place. Turn it round until you can see through the hole where the punch pin will go. Take the punch pin and tap it into place until it is central in the shaft and does not stick out on either side. Again take care not to mark the enamel with the hammer.




REASSEMBLY - TOP COVER

Place the top cover back on the machine and secure it with the four crosshead screws.



Put the silver flexible band in its groove round the top cover and secure it with the single screw at the rear. The end of the band with the serial number printed on it should be on the top.




REASSEMBLY - TESTING

Make sure the speed selector lever is in the Off position and plug the machine into a socket.

Move the speed selector lever forward slightly to the slowest position and be prepared to switch it off if necessary. Allow the machine to run at the slowest setting for half a minute to spread the grease evenly around the load-bearing parts. Only then should you gradually increase the speed until the machine is at full speed.

It is then safe to turn it off and return the machine to service.

Of particular interest is how much less grease this new style of gearbox requires when compared to the older models with the worm gears. They required a large grease "reservoir" to be packed into the gearbox that would melt and flow into use as the old grease degraded and parts heated up.



I am under the impression that this new gearbox style is much more efficient and should last a lot longer. This machine has been in use for five years of domestic use exclusively on speed 2 for dough making without any maintenance.

After cleaning I inspected all components for wear under magnification. I only found slight polishing between the accessory shaft gear and 90-degree planetary gear. There was also slight wear between the bottom of the 90-degree planetary gear shaft and the planetary ring which I believe was due to no grease being applied at that location by the factory.

Once reassembled I found that the machine ran much quieter under light load and when mixing heavy dough the regular "click click" noise as the planetary ring turned was still present but significantly reduced.

I hope this guide proves useful and will endeavour to keep these pictures uploaded in the long term. On the offchance that my hosting provider changes, here is a link to the pictures as a 7ZIP which the Forum Moderators may wish to secure a copy of.

ARCHIVE : PICTURES AS 7ZIP

Good luck,

Daniel.

PERMISSIONS : I am happy for this guide to be re-posted anywhere whole or in part along with the relevant pictures PROVIDED it is for NON-COMMERCIAL purposes and that I am CREDITED as the original author.

DanielCoffey's picture
DanielCoffey

Finally, permissions...

PERMISSIONS : I am happy for this guide to be re-posted anywhere whole or in part along with the relevant pictures PROVIDED it is for NON-COMMERCIAL purposes and that I am CREDITED as the original author.

suave's picture
suave

Thanks, this is going to amazingly useful to many people.  It's too bad that my KA is a much older KG25H0X.

barryvabeach's picture
barryvabeach

Great photos and write up,  and I don't even have one of these, though it looks well made. 

Galaxie1964's picture
Galaxie1964

Great Guide. Really detailed an with good pictures.?

My KitchenAid is stuck on the planetary gear.

But on my enamelled planetary ring, there are no punch pin. Would you know how to disassembly it?

Regards

Søren

DanielCoffey's picture
DanielCoffey

I would assume that all KA machines of this model number would be built in the same way. Without knowing what model you have and perhaps a picture of the planetary, folks won't be able to help.

Galaxie1964's picture
Galaxie1964

Here is a picture showing the planatary ring, and from top as well.

 

DanielCoffey's picture
DanielCoffey

Is it possible that it is painted over? I really don't know how they could assemble it without a pin in that location on the underside.

Without damaging the paint perhaps have a very close look in good light to see if you can spot any signs of a ripple in the paint?

Galaxie1964's picture
Galaxie1964

I have just checked, and there are no pin.

Could it be the little lock ring, I have pushed down is the only thing holding it? 

DanielCoffey's picture
DanielCoffey

I suggest you just use a kitchen cloth to clean what grease you can and reapply where it is accessible.

Without being able to tap out the push pin that is normally there, I don't know how the planetary unit is anchored on your machine.

Sorry I can't help any more but I don't know what else to suggest.

Galaxie1964's picture
Galaxie1964

Ok, thank you. 
However, the gear is stuck so I need to get it off somehow.

I will let you know if I sort it out.

Melbourne Park's picture
Melbourne Park

Your mixer doesn't look the same as the model which was taken apart. Please post your model number and serial number. The shape of the underside is quite different to the model discussed. Perhaps a couple of photos from the top would clarify which mixer model you have? Good luck.

DanielCoffey's picture
DanielCoffey

There should be the model number on the back of the decorative band too.

Galaxie1964's picture
Galaxie1964

Yes, its correct it is not quite the same version of machine, but it is the only other I have seen with the same gear conficoration on top.

the model is KP26M1XES5, and serial is W25114058.

 

Melbourne Park's picture
Melbourne Park

High Galaxy,

I suspect your machine is a 6 litre lift stand mixer. The mixer has an entirely separate gearbox from the motor. The 7 litre and 8 litre units, I think if a motor or gearbox fails, one has to buy both together. 

You can buy parts for the machine, and also, there will be lots of videos on youtube showing you how to remove the gearbox etc. 

Start at this link maybe and I would treat the machine as being the 6 quart model. Good luck.

https://www.partselect.com/Models/KP26M1XES5/Sections/BASE-AND-PEDESTAL-UNIT/?ModelID=1914919&ModelNum=KP26M1XES5&mfgModelNum=&ManufactureID=3&Selecte...

 

Melbourne Park's picture
Melbourne Park

Hi, thanks for a great review. Incidentally this person who did a video left the electrics attached. Would it be possible to do so while replacing the gearbox's grease? https://www.youtube.com/watch?v=__XlxMGs_aY 

I have just been delivered a 7 quart (240V 6.9 litre) model for home, and its fabulous. I am wondering how many hours or how old your machine is? 

 

Thanks for the great report and fine pictures. 

 

DanielCoffey's picture
DanielCoffey

My machine was used at home only for about 5 years of roughly weekly bread dough mixing.

Melbourne Park's picture
Melbourne Park

So Daneil, please excuse my curiousity, but did you need to take the machine apart, or was it preventative maintenance? I know these days with motor vehicles, manufactures are saying their gearboxes are good for the life of the vehicle. I don't believe that, so I have had my gearbox lubrication changed. But I wonder if 5 years is the right time? What was your grease like, had it gone solid anywhere?

Cheers and thanks for the great contribution here. 

Doug

 

DanielCoffey's picture
DanielCoffey

It was preventative because after five years of making dough I was getting increasing noise from the planetary under load once the dough was coming together.

The original grease was fairly dry and pushed out of the way but I would say that it was still doing its job. I decided to try to learn how it was put together and renew the grease.

Melbourne Park's picture
Melbourne Park

Thanks Daniel. I might do the same in 5 years. I was going to take a photo showing the temperature of the mixer while mixing about 1.8kg of dough - two decent sized loaves for me. But the camera's battery was flat - I will try again next time I do some dough and I'll post it here. The temperature of the gearbox was cool for some time, but as the dough stiffened after quite a while, then the gearbox became warm. The motor became warmer, but after some time also. 

 

DanielCoffey's picture
DanielCoffey

The motor is rated for a fairly short duty cycle too. It is stencilled on the motor itself next to the serial number. I believe the rated duty is 10 mins on, 15 mins off. That is why a large amount of dough (at speed 2 only, remember) will heat everything up.

Melbourne Park's picture
Melbourne Park

The motor rating being only 10 minutes seems somewhat contrary to having the mixer sold as a commercial machine. That would mean that you could only use the machine 40% of the time. While that would work for a commercial environment over a whole working day, 10 minutes seems to short. The warranty for commercial use though is two years. Most Kitchenaid mixers are two years, but for non commercial, its 5 years. 

Strange thing about the dough usage is that there is a video of the 8 quart commercial machine made for the Indian market (their machine resembles how we get a commercial one in Australia, which a stop switch being a difference to ones I have seen for the American market). In the Kitchenaid video, it's about making dough. And the presenter says its best to run the mixer when making dough, at speed 6! Not the restricted speed of 2 ...

I have also made bread with a dough hook supplied with a single speed Cuisinart brand Food Processor. It has a separate button for dough. It's single speed, so the machine runs very quickly. It takes very little time to get the dough to a reasonably worked, resilient state where is pushes back after pressing into the dough. So, IMO running the Kitchenaid at for instance a speed of 6, should take a lot less time. And perhaps, it would work the motor less. However, doing that might work the gearbox harder I assume. So, perhaps a higher speed would reduce the overall "work" the motor does for dough work, because if it's "worked" at a higher speed, then the time would be reduced? 

A good feature with the machine is the temperature protection. I don't know how that works though - whether their is a thermocouple inside the motor, or whether its entirely different, such as a calculation done on the mother board. 

One good thing though - the DC motor is more efficient than other motors used for Kitchenaid mixers, and since its pulling more power but using it more efficiently, I reckon it would last longer than other kitchenaid mixers. I also have not heard of a motor failure. 

I am actually not worried about burning out the motor, or the gearbox, or changing the brushes. Pro service people say that changing the brushes is quite difficult, as they are not designed to be changed. However I have read repairers say (which was in a 2018 article though) that a motor and gearbox replacement was only $80. The repairers were saying since the gearbox/motor part was quite cheap, there was little point in for instance, changing the brushes, or taking the time to pull the gearbox apart, clean the gears and then replace the grease. Instead of simply putting in a new motor and gearbox unit.

 

 

Melbourne Park's picture
Melbourne Park

The motor rating being only 10 minutes seems somewhat contrary to having the mixer sold as a commercial machine. That would mean that you could only use the machine 40% of the time. While that would work for a commercial environment over a whole working day, 10 minutes seems to short. The warranty for commercial use though is two years. Most Kitchenaid mixers are two years, but for non commercial, its 5 years. 

Strange thing about the dough usage is that there is a video of the 8 quart commercial machine made for the Indian market (their machine resembles how we get a commercial one in Australia, which a stop switch being a difference to ones I have seen for the American market). In the Kitchenaid video, it's about making dough. And the presenter says its best to run the mixer when making dough, at speed 6! Not the restricted speed of 2 ...

I have also made bread with a dough hook supplied with a single speed Cuisinart brand Food Processor. It has a separate button for dough. It's single speed, so the machine runs very quickly. It takes very little time to get the dough to a reasonably worked, resilient state where is pushes back after pressing into the dough. So, IMO running the Kitchenaid at for instance a speed of 6, should take a lot less time. And perhaps, it would work the motor less. However, doing that might work the gearbox harder I assume. So, perhaps a higher speed would reduce the overall "work" the motor does for dough work, because if it's "worked" at a higher speed, then the time would be reduced? 

A good feature with the machine is the temperature protection. I don't know how that works though - whether their is a thermocouple inside the motor, or whether its entirely different, such as a calculation done on the mother board. 

One good thing though - the DC motor is more efficient than other motors used for Kitchenaid mixers, and since its pulling more power but using it more efficiently, I reckon it would last longer than other kitchenaid mixers. I also have not heard of a motor failure. 

I am actually not worried about burning out the motor, or the gearbox, or changing the brushes. Pro service people say that changing the brushes is quite difficult, as they are not designed to be changed. However I have read repairers say (which was in a 2018 article though) that a motor and gearbox replacement was only $80. The repairers were saying since the gearbox/motor part was quite cheap, there was little point in for instance, changing the brushes, or taking the time to pull the gearbox apart, clean the gears and then replace the grease. Instead of simply putting in a new motor and gearbox unit.

 

 

Gordon Gallacher's picture
Gordon Gallacher

Hello,  thanks very much for providing such fantastic instructions for dis-assembly etc .  I wonder if you could advise please?  

I have the model 5KSM7591, like the one you show.  The planetry has broken into two pieces, one of them just fell into my dough one day!  Well, I tried to get the other half off - found the retaining pin and pushed it out, but the other part simply won't move - I tried pulling at it quite strongly but it won't budge - though I can push it round ok.

Any thoughts please?

thanks

Gordon

 

DanielCoffey's picture
DanielCoffey

I am amazed that the entire planetary cover could crack in half! Did it receive a knock?

I assume you are talking about the part I remove in pics 6 and 7 (counting from the top of the post), yes? If that is correct then on my machine the only thing holding it in was the pin.

Can you attach (or link to) a picture of what is stuck?

Gordon Gallacher's picture
Gordon Gallacher

thanks for your speedy reply...

Photos below...

The machine has not been knocked or anything like that, though it has been well used over some years.  I had a feeling something was going to go wrong, as it had been making an odd noise the couple of times I used it before the breakage.
I'm rather keen to fix it though, as I see the new ones are now well over £700 !

thanks again
Gordon 

--

 

DanielCoffey's picture
DanielCoffey

Wow that is a catastrophic failure! Fortunately I think the planetary cover and associated gear is available as a spare (maybe not colour matched).

 

With the horisonal pin out, that is all that *normally* holds the planetary cover in place but with that much damage it is posible that the polished shaft is being pinched by the remants of the cover. Be careful trying to pry it loose in case you dsamage the vertical shaft that comes down through the top deck.

 

See if you can observe any play in the broken piece if you use a flat screwdriver to tap and try to rotate it near its outer edge where it curves up towards the main body. Don't belt it - just see if it wants to move first one way then the other.

 

If it does come off, you may need to clean and inspect the vertical shaft carefully for damage.

Gordon Gallacher's picture
Gordon Gallacher

thanks Daniel,

Still can't get it off.  I can turn the planetary  - a little - on the main shaft, but it sticks.  I suspect the shaft itself has got damaged/warped, jut enough to hold it fast.  There must have been something that caused suficient strain to shatter the planetary itself, so maybe that was it.  There was no unusual load on the mixer at the time - just the same as I often have used over the years.  I've now tried everything I can think of to release the remains of the planetary, so unless there's something else you think I can try, looks like I'll have to scrap it.  It's been a great mixer I will say.

 

Cheers

Gordon

 

DanielCoffey's picture
DanielCoffey

It is possible that the back end of the machine contains useful spares... the main board, the motor (and just possibly the gearbox).

north_by_midwest's picture
north_by_midwest

I would bet the shaft is probably not at all bent and the orbital has crimped itself on when it split apart. Have you considered taking a hacksaw or rotary tool to the orbital assembly? The housing is relatively soft metal and that shaft is probably very hard so you can possibly separate the two parts further destroying the orbital bit but leaving the shaft mostly unscathed.

Gordon Gallacher's picture
Gordon Gallacher

Thanks,

The main shaft does appear to be very hard steel, so it would be strange if that was damaged... I don't know, I'll certainly try and get a cutting tool to the remains of the planetary, but it's going to be hard to get in there. The fact I can move the planetary about an inch or so round the cental shaft - what does that imply?

thaks again for your suggestions

Gordon

karacik's picture
karacik

Thank you for this guide! The detail is incredible. I have two of these mixers, both new. One has a metal case (made in China) and the other has a black case and two bands (made in Vietnam). I don't know what the exact material of the black case is, maybe its plastic, but wondering if it has any effect on the quality of the mixer? Is it insulating? What is underneath the case? I don't know anything else apart from the country of manufacture. I would appreciate any insight.

Camarie's picture
Camarie

You couldn't even PAY me to ever put any trust into another KA mixer ever again!!!! Especially since Whirlpool took over & cheapened the quality of these once- popular machines!!!!!!!!!!!!

karacik's picture
karacik

I have never owned a KitchenAid mixer before this, and now I understand the growing hatred hah. I recieved the kitchenaid mixer as a birthday gift. Ill be honest I wanted a Kenwood or a pizza mixer (ill get that soon enough!). The experience turned into a nightmare. KA sent me soiled display stock that looked like it had been to battle, then that was replaced 4 more times, each time with "brand new" faulty, damaged machines that were leaking grease and grinding when turned on. Thankfully they will be giving me a refund but I will still have a mixer to keep, not sure which one to go for- metal or non metal. They both have oil leaking all over the speed control and down into the machine. I will eventually repack the grease. 

DanielCoffey's picture
DanielCoffey

Can you keep this on topic please. The 5KSM kitchenaid models cannot leak grease on the speed control as there is nothing lubricated near that area.

karacik's picture
karacik

Ooh sorry! Regarding grease, I was told by KA they can leak oil to that area if they are stored on their side. The oil shouldnt be seperating so early in the life though 

Miguelito's picture
Miguelito

Hi from Germany ,

does anyone know a shop for those gears or the complete gearbox?

DanielCoffey's picture
DanielCoffey

I suggest you look on your local eBay to see if there are folks selling the motor in your area. I know there is one in the UK and there also appears to be one Australian repair shop doing the same.

Miguelito's picture
Miguelito

There’s a lot on local eBay for the small machines, but nothing for the heavy duty’s…

Miguelito's picture
Miguelito

There’s a lot on local eBay for the small machines, but nothing for the heavy duty’s…

Dewey3491's picture
Dewey3491

Daniel,

Was your planetary gear hard to remove (like stuck) and was it also hard to reinstall? I am doing a service on a Kitchenaid KSM8990 which is a 8qt commercial model and can’t get the planetary gear back on with out using a mallet.

DanielCoffey's picture
DanielCoffey

No it wasn't stuck at all. It turned freely and was held in with a circlip which slotted into a groove.

Dewey3491's picture
Dewey3491

I am going to take the planetary gear housing to a machine shop to open the hole the transmission shaft goes thur. At the I will be able to get on and off without using a mallet to pound it on.

Dewey3491's picture
Dewey3491

Daniel

what is the trick to get the hall sensor connector from the speed control board to release from the motor?

DanielCoffey's picture
DanielCoffey

From what I can remember, the part of the plug you need to release has a small protruding but flexible tab that catches onto part of the socket on the board. I think if you look closely under bright light you may be able to see which side it is on (I don't remember if it was on one end or a flat side).

I used a slim flat bladed screwdriver gently down that side of the connector to release the tab. It won't take much force and care must be taken not to snap the side of the socket on the board. It will not take much pressure at all. You merely need to get the plug tab to release from the socket and it should slide straight up and out under light finger pressure.

Dewey3491's picture
Dewey3491

I got it unhooked today. Thanks.

Dewey3491's picture
Dewey3491

Daniel,

We thanks for the pictures it help putting the gearbox back together. I had to take the planetary to a machine shop today along with the gear box. It appears the the down shaft the planetary connects to took some side load and caused the shaft to swell making it difficult to remove and install the planetary to the shaft. It tried to remove the shaft from the gearbox housing and it will not come out but it does spin. The washer on the shaft do you know the thickness mine is to thick because the snap ring will not go into the groove. Also the place to of the small gears mine had the thicker gears closer to the motor I think they go the other way because I could not get the gearbox on the motor until I switched the around.

 

DanielCoffey's picture
DanielCoffey

I don't know the thickness of the c-clip but a feeler guage in the groove on the planetary shaft will give you the maximum thickness.