ChrisCobb

HI !

I have a 98 A8 that I bought at 120k miles last Oct. I was told it has a rebuild transmission around 90k before I bought it, which I of course assumed that meant it would run fine for 100k more.

Anyway as I did not know when the AT fluid was last changed and it was making the odd noises that I now think are normal.. but I dropped the pan last Nov, replace the gasket, filter, and put in about 7 quarts of the pectin. Yes the fluid was black, but it did not look that bad and did not smell bad. (yes i got covered with it as I was doing this on car ramps :-) ). One odd note, the normal magnets were not in the pan.

Anyway 3 weeks ago I got the dreaded clunk as I was leaving the driveway instead of shifting to 2cd gear, and the famous limp mode. I have put the vag-com on it and it clearly seems to be the normal "cracked clutch A housing"

Anyway my questions are:

1. Can I put in a newer model A8 tranmission, say a 01/02 that does not seem to suffer from the same transmission issues?

2. If not what ZF transmissions should I request? is there a better version to use ?

To quote Gabor "You can use any 5HP24A tranny in your car CUE, DPZ, DSL, DSM, DTD, DTE, ELZ, EDG, FBE, FBF, FUM, FUN, GLA except the S8 tranny DYM, ECX, ECY, FBG."

So which ones are "better", I think I have DTE now ?

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It seem the A8 d2's suffer from constant Torque converter slipage (leading to wear, then plugged filters/etc.) thumping/hunting, blown seals, etc.

Some of that I think is related to the transmission control unit firmware.

Please advise !

tozoM8

You can use a newer tranny. I had a FUN in my 97' for a while.

pkrasusky

au contraire sir - I'd argue that you have a FUN in your '97 NOW 8-)...

CalG

Tozo

With but two shaft speed sensors, a shift position device and a handfull of fluid control solenoids, and a fluid temperature thermister, What limits the use of the transmissions designed for the S8s?



Morbid curiousity. I should really look at the electrical diagrams. Oh! another Bentley :-(

Cal

tozoM8

Yes, I love it more and more every day. It will be hard to find a replacement.

tozoM8

If I had an A8 I would put an S8 tranny in it.

Figure 11

Different gear ratios. Also probably need matching rear diff.

Mike

CalG

Is setting up the diff too daunting a task? Requiring many "special tools"?

Or could a swap from the A8 donor be considered?

Cal

tozoM8

pre-facelift 2.7 post facelift 2.9 S8 3.7. I would try to get a 3.3-3.4 final drive for the A8.

ChrisCobb

Hi !

So if I can get FUN tranmission, it just plugs in?
any issues with the changes? What are the advantages of a FUN over say a dsm/dte?