First time change on AT fluid (twice) and front diff oil, with noticeable improvement.
Quote:
Originally Posted by upallnight
Can you elaborate on the improvement? How was the old fluid in the trans and diff?
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The ATF was ridiculous. Looked like a black soup of microscopic particles. Certainly original. New filter, cleaned pan, drained overnight to remove 7 qts total. Replaced with Dexron VI, which is the current spec for the A5S 390R in my 2001 3.0i.
It immediately felt like the car had less drag, shifting much smoother and faster. For example, prior to the change I did not find the steptronic shifting responsive enough to use comfortably, so I never did. I do now (just for fun). I can now feel it quickly and smoothly shift through each gear on all types of acceleration.
I drove like a granny for a few hundred miles, concerned with the stories of some gunk breaking loose, getting stuck in the wrong place, and having the AT destroy itself. I figured if something were to break loose and I was driving gently, there'd be more chance for things to sort themselves out before catastrophic damage.
Since the fluid was so bad, I did another change (new filter, 7 qts Dexron VI) after 400 miles. The fluid was not quite so bad, but still so dirty that I'm glad I changed it. The capacity is spec'ed at 9.5, so in theory there was only 2.5 qts of the original dirty oil, but I guess that's a lot if it is really dirty. The pan was not so full of fine particulate debris this time, but I did find one pea-sized glob of goop sitting on the pan. I also found one shard of a gear tooth (had found none in the first change) - but it was tiny - about 2mm long and seriously only about 0.1mm diameter - would have been invisible except it was very shiny. So this supports the legend of new fluid shaking loose dangerous goop, but I survived.
Driving maybe improved a little more following this change, but not as dramatic as the original one. 500 miles since the second change. I'm actually considering doing a 3rd one later this year - very cheap to do with Dexron VI, and now that I've figured out how to do it carefully.
Front diff oil - that looked black too, with just a couple of shiny flakes. I expect it was original just based on the overall philosophy of the PO. Also, the rear diff oil was dirty, but noticeably cleaner, which makes sense because that is much easier to change - he probably had it changed at jiffy lube or something once. Performance - the only thing I can say there is that I remember driving the car home after buying it and could hear some front drive train noise (I figured it was normal) at freeway speed, and now I don't hear anything like that.