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Old 12-07-2010, 11:13 PM
Starless Starless is offline
Location: STL, MO
Join Date: Sep 2009
Posts: 1,712
Mein Auto: 2002 325i Auto
Originally Posted by kjsgadh View Post
Hello all.

First of all thanks for the great write up Starless.

Second, I have a question. I had my ATF fluid changed by a reputable local indy (Curry's Auto, Falls Church, VA) at 95K miles. They used a trans flush machine, so the pan was not dropped and the filter not changed. They also used BG Universal ATF. Details at I have not been able to find much detail on this fluid.

While researching the issue of idle dipping when changing from Park/Neutral to Reverse/Drive, I ran across the large number of threads reporting reverse failure on the ZF 5HP19, which is what I believe I have. I have a 2001 330i (produced June 2000). And I am becoming partially paranoid about the transmission.

I was contemplating replacing the fluid again with one of the appropriate fluids listed by forum members. I was thinking about draining the fluid from the fill/drain plugs and dropping the pan, replacing the filter, but refilling through the trans cooler lines using a hand operated air pump, in order to replace all of it at once. I have not seen any one on here taking that approach.

I just wanted to run it by everyone else here to get their opinions about what they thought. If not this, then I would have to drop the pan and replace the fluid at least 3 times to get close to all new fluid in there.

Please advise. Thanks in advance.
I have heard about this way of doing this (thru the lines) and about the people who have done it this way but I'd really need to research it more to do it myself, however theoretically it make sense and so on. But instead of your idea of hand operated pump it's usually done by starting the car and letting the transmission pump circulate the atf untill fresh fluid comes out. Well, I've never tried it and I'm not sure I want to mess with it.

However what I am going to do next time is disconnect both lines from the transmission cooler and let the ATF drain from them and from the cooler with the purpose of draining still more fluid.

And by the way, you do have ZF I believe, my write up is for GM, but Torquewrench has an awesome write up for ZF in DIY section of the forum. ZFs are known for weak reverse drum. There is a Reverse Drum Replacement DIY on fanatics. GMs' reverse problem is the wear and failure of certain valve body components due to the thin aluminium used for making the GM valve body. The replacement of the valve body and/or installation of the Sonnax valve body kits solve this problem in case of the GM transmission. ZFs often need a reverse drum though.
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