928 U.K.

hi

I have taken out the auto tranny from my 84 s2 and it is lying on my bench now nice and clean. should i take it to a specialist to have it fixed or could it be fixed at home b

thanks

Tim 84 s2

WallyP

You can rebuild it yourself, IF:
You have the Factory Workshop Manual covering your transmission.
You can read, understand and follw technical directions.
You have some mechanical understanding and experience.
You have the necessary tools, such as torque wrenches.
You are willing to buy some special tools.
You have the capability of cleaning the parts.
You can buy the necessary parts, seals and gaskets.
You have room to spread the parts out and keep them straight and organized, and the parts will not be jumbled by the cat or the kids.

A digital camera is very valuable.

928 U.K.

Wally

i have the manuals i am a precision engineer by trade i have the space i am interested i have the patience and i have the time so am i a candidate to do the rebuild?

p.s where can i source the new parts? is there a rebuild kit available?

cheers

Tim 84 s2 auto

WallyP

Call David at (828) 766-9280 to discuss what you need. We can supply any part available from Porsche for your 928, plu many aftermarket/OEM parts and accessories.

928 U.K.

Cheers Wally

after speaking to a gearbox specialist over the weekend he said the amount that i would need to spend on special tools/pressure tester e.t.c would be more expensive than an on the bench rebuild
the specialist said that he would charge from £400 sterling but he would strip it and give me an estimate first
he has done a lot of merc boxes before and he is very familiar with them
is there any hints that he needs for the rebuild as the box is out of 928 and not a merc

many thanks again

Tim 84 s2 auto

WallyP

Perhaps Steve C., our resident transmission expert would be better to answer that, if he is monitoring this thread.

Steve Cattaneo

Tim,
The rebuilding procedure’s for the A28 transmission (928) and Mercedes transmission (722.3, 4speed) are the same. The factors which will guarantee a successful rebuild are, experience, it plays a major part in deciding which parts can not be reused, bad hard parts, planetary gears, ring wear ext. Experience also comes in handy when diagnosing a rebuilt problem. Transmission not shifting right, slipping, delays into gear, and not every rebuild is a success. The second is technical information, updates made to the transmission; the rear band piston (B2) was updated, as well as the front servo piston. The rear pump, which is used to push start the car was disabled. There is a kit from Mercedes for this update. There is a shift kit for the valve body, very useful for shift feel.

To insure a successful rebuild #1, have the torque converter rebuilt, not just flushed out. This is where the contaminated parts from the transmission like to hide. #2- they should rebuild the planetary gears; there is a kit available. #3- installs a new modulator it is the load input for the transmission.4, change all the sealing rings, O-rings, clutches, lip seals, sealing rings, if the steal plates speck out deglaze them. #5- check band and drum clearances. #6- flush the transmission cooler thoroughly when the transmission is out. #7- when the rebuilt is finally installed, check and adjust modulating pressure with a gage, check and adjust the T.V. cable, check fluid level. #8- the most important factor that will insure a success rebuild in an A28/MB transmission is to change the secret O-rings in the drums.

If you need any more information I am sure Wally and I can help.

<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

928 U.K.

Thank you Steve

When i flush out the cooler is there a procedure that i should follow and what should i use to flush it with. I will do this while the box is being rebuilt

Thanks again

Tim 84 s2 auto

928 U.K.

The auto trans man said that the tranny was contaminated as at some time water had got through the oil cooler in the rad which i had reconditioned about 3 years ago
i am also having the torque converter reconditioned and the rad tested again