bdeneen

I wanted to bounce this off some people since it appears to come up ofter in the forum.

jibmaster1 had a post a while back about a metallic sound coming from his tranny or TC about a month after he performed a fluid/filter change. I did a little research since I had recently done a similar change at 65k and was concerned that this may happen to me as well. I believe he said that he did his at 100k.

Anyway I came across some info that seems to explain the whole "late fluid change phenomenon" quite well.

Over time the fluid will oxidize and begin to varnish and form some sludge. The idea that it can be "too late" to change transmission fluid is based on the potential that so much varnish and sludge has built up in the transmission that the detergency of new fluid will soften, loosen and break up this material and cause it to clog hydraulic passages, potentially leading to transmission problems.

My guess is that this is what is happening to jibmaster1's car. restricted flow is causing the "metallic" whine.

An acquaintance had a similar problem with an A8 he had recently changed the TC on. His remedy was to run it at about 120mph for a few miles. Apparently that took it away. Of course he picked up the vehicle for 3k and didn't have much to loose.

Any real mechanics want to chime in. I am just a hobby mechanic. An excuse to take the tie off and get dirty.

finiki

Mine was changed due to a leaking pan gasket around 70K. Given a choice I would not have done it. It is not recommended, who am I to disagree. Once it was done it squealed like a pig as it wound up. Now 10k later it is not doing that. Your hypothesis could be right. In this case new fluid, like Lipitor, cleaned the pipes? Will it prolong life like Lipitor? In life, as in allroads, who knows?

jibmaster1

Great. Did the sound decrease after tranny fluid warmed?

finiki

Was not paying that much attention to notice.