Re: Trannys

From: Karl Kromer (karlk@ssl.berkeley.edu)
Date: Tue Dec 02 1997 - 11:45:51 EST


>Someone once advised me NOT to change the Transmission fluid because
>it can do more harm than good. I have pretty much disregarded his
>advice but does anyone have any reasons why he would tell me that,
>other than he wanted to sell me a transmission?
>
>Dave

I have heard this as well, but only in cases where the fluid has been
neglected for long periods. The two possible reasons I can think of are:

1. The neglected fluid has lots of crap in it, which deposits itself all
over the tranny. Fresh fluid might break this stuff free, clogging the
complex hydraulic passages and/or ball valves, thus rendering the tranny
useless.

2. The neglected fluid changes chemically with age, "loosing" the additives
for friction reduction & oil seal health. The seals swell over time because
of this, and there is extra wear on them at the seal/shaft interface.
Changing to fresh fluid could cause them to shrink back to normal size,
causing all kinds of leaks because they no longer seal against the shaft.
The same would go for o-rings.

These are just educated guesses; maybe this is just more BS from tranny
shops to get you to neglect your transmission.

-Karl



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