Final drive fluid test?

[David Head]

The fluid in final drive 'transfer' was a problem in the old auto 3 
speed fwd trannys. The Transmission was hung on the back of the diff 
with a hollow dual drive shaft setup - the center shaft (inside the 
hollow outer shaft) drove the trans pump. There was a paper seal and 
huge o-ring between the two assemblies. There were many service 
bulletins on this problem. In reality tho, mostly these trans suffered 
from internal leakage problems due to wear between the case and shift 
pistons. That also made them nearly impossible to rebuild - the case was 
shot. This trans was used until 1990 (also used in VWs), replaced by a 4 
speed unit that had nearly as many problems. Audi didn't have a really 
reliable trans until 92 up models.

I went through about 5 of these trannys (mostly junkyard spares) in my 
old 79 5KS, and a diff assembly once. Only the diff and one trans 
failure was due to leakage into the diff. The diff bearings went bad 
first after an extended 120mph run between Tucson and San Diego. I 
finally found a good VW trans rebuilder who told me how the cases went 
bad. Bought a rebuilt one from him and a new converter, no further problems.

I got quite adept at pulling them - you can actually pull the trans 
without the diff if you know what you're doing...

Dave C. wrote:

>If anyone knows of an actual incident where ATF leaked into the final drive
>(or the reverse) I'd like to know about it.
>----------------
>Dave C.
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