Gearbox Teardown & Refurbish - 6HP28A61

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Invert the planetary gear and remove the lower needle bearing and inspect, again all good

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It looks like we are making progress but really we have only scratched the surface so far...


Remove the flat bearing washer from within the planetary annulus



Invert the annulus and remove the large circlip holding the output shaft to the annulus gear, you need only do this if you are a little OCD on cleanliness like me; they can be left together

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Now lets go back to clutch B and strip down the clutch pack itself


Starting with the circlip holding the clutch pack in place



Keep it together for later inspection


Now we need the use of the press for removal of the clutch piston retained by a stiff spring and circlip. ZF have some good tooling for use with the press, but as usual I dont believe in buying something we can be inventive with. Had I not run out of shield gas I would have made the 3 press tools (you will find lots of google images on these and they are easy to make with some flat bar and a welder) Given I dont expect to have do this job twice I didnt think it was worth it anyway. So I rooted through my scrap steel and came up with some odds and ends to do the same job - to press against the piston and spring so the circlip can be removed without any tension on it. In this case an old double bearing race from a 406 Peugeot fits nicely...

Oh and ZF recommend an arbour not a hydraulic press (presumably so you can control the force and not stress the components), but the hydraulic press works fine if you are careful


Just compress the spring sufficient to remove the clip, no more than necessary

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Now remove the circlip


And the retaining washer



And the spring of course


That leaves us with the piston itself and the retaining plate


Remove the circlip against the retaining plate


And pull, in my case the piston came first, with the retaining plate; depending what you pull on you may get a different result, but the bottom line is you need to pull out the piston and release the retaining plate from the piston to get to all 3 of the O-ring seals


2 of the seals sit in the piston

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And the third O-ring seal is on the retaining plate

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Back to 'body II' (Clutches A and E) which is still sitting upside down in the workbench with the input shaft pointing downwards, remove the circlip retaining the rear inner plate carrier


And remove the rear inner plate carrier


On the bench withdraw the inner plate carrier B

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Leaving us with the inner plate carrier A


Turn this over and remove the needle bearing and inspect it, all good

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Back to the 'body II' assembly and withdraw the inner plate carrier E with its intermediate shaft



Inspect the bearing and seal faces visually and with your nail, no problems here

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Now we can actually get to the clutch E pack


Unclip the needle bearing and inspect, no surprises here either



Withdraw clutch E from clutch A



And invert it on the bench


Remove and Inspect the needle bearing, in my case this was particularly stubborn and would not unclip; given it passed the inspection I decided not to mawl it off (and damage it in the process) and to leave it in situ

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Remove the 3 Rectangular section seals




Flip over clutch E and remove the circlip


Remove the frictions and steels

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Another visit to the press and the same old bearing race fits nicelyagainst the piston, albeit a bit snug for getting the circlip off


Remove the circlip


Remove the retaining washer


and remove the retaining plate and spring

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A gentle tap upside down on the bench and the piston will fall out, or you may have to persuade it a little
If it simply wont play ball you can apply air pressure to one of the oil bores on the shaft whilst covering the others to blow it out

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Now onto the last part of 'body II', Clutch A


Unclip the oil collector


Next up is real tricky sod, you need to place a small screwdriver up in between those outer notches and the planetary gears - there is a circlip on the inner edge holding the planetary gear assembly in place, you need to lever this clip out of its seat in the four points around the gears. You will need a torch to see it and a lot of patience




If we now flipthis upside down
That's the sod there, if you want to replace this one its ZF code 0730.513.825, the book recommends you do so
You can also clearly see the four inner recessed notches you need to get the driver onto to pry this clip off (easy to see now, not so easy with this in situ!)


Now lift out the sun gear


Unclip and inspect the needle bearing

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Now to remove clutch pack A, unclip the circlip


And withdraw the frictions and steels



And back to the press to release the piston, here I used an off cut of an old pipe (5" I think)





And remove the circlip; this one is recommended to be replaced, not by the book though (it was a personal recommendation), ZF code 0730.513.792 - So I did replace it

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Remove clutch A retaining plate



And spring


Its doubtful you will be able to pry this piston out very easily, so dont struggle - drop it back onto the pump housing and apply air pressure to the relevant port on the pump housing to force the piston out; you dont need masses of pressure, a bar should do it. The bore you are after is the third bore to the right of the ATF strainer inlet (assuming you have the strainer inlet directly in front of you as shown)