I have a transmission leak on a 2001 Buick Regal LS with the naturally aspirated 3.8L and 4t65-E transmission. I saw the fluid collecting around the pan on the firewall side of the transmission. Looking closer at it the fluid was coming from farther up. I took some parts off and found the reverse servo cover is leaking. The rear exhaust manifold is right over the cover and it seems like it will be hard to press a new seal in unless that manifold is removed. Has anybody replaced this lip seal with the tranny in the vehicle? If so, do you have any advice?

I've not done it in a car, but you should be able to remove the cross over pipe and get at it. You will need to remove the retaining clip, then the cover will come up. There'* springs under there so be careful. Make note of how the parts and seals go in. If you have a ATSG service manual, you will need it. The O ring seal needs to go in the correct way. Also make sure it'* the reverse servo cover that is leaking. The transmission vent is a little above that. If that'* leaking then you my likely have a blown channel plate gasket.

I agree!

I've not done it in a car, but you should be able to remove the cross over pipe and get at it. You will need to remove the retaining clip, then the cover will come up. There'* springs under there so be careful. Make note of how the parts and seals go in. If you have a ATSG service manual, you will need it. The O ring seal needs to go in the correct way. Also make sure it'* the reverse servo cover that is leaking. The transmission vent is a little above that. If that'* leaking then you my likely have a blown channel plate gasket.

I removed the cross over pipe (stripped a flange bolt out in the process) and still couldn't get to it. The rear manifold wraps around right over the reverse servo cover. After removing the full exhaust system and the rear manifold I got it apart. From what I understand there is an upgraded cover and seal. Does anybody know what the part number is for this upgraded part? Oh, and the vent was dry luckily. After taking the throttle body off I also noticed that the lower intake manifold end gasket is leaking oil, so that is the next project. The car only has 64k miles on it and it'* a 2001. I'm guessing I'll have a few gasket/seal issues due to lack of driving and excessive sitting. Oh well. Thanks for the help.

I do not know of any upgraded cover for the reverse servo.

As for your leaking oil, that'* likely the seal under the LIM the encloses the lifter valley. When you change these I strongly suggest getting the new aluminum framed LIM gaskets. There'* a write up in techinfo, I believe it'* in mechanical or maintenance, can't remember. Fairly easy job, give yourself 4 hours. Takes me about 2 hours.

Yeah I plan on putting the perma dry plus Fel-Pro gaskets in it. I've done about 5 or 6 3.1 liter intake gaskets, but never on a 3.8 liter. Thanks for the information. I am thinking about installing the new upper intake to avoid the risk of the EGR burning the composite and causing problems. Here is an upgrade kit I'm looking at http://www.ineedparts.com/auto-parts...kit-17806.html . Any experience with it?

Check at ZZ performance, they have one for $60

Do you know what the orientation of the lip seal is supposed to be. Looking at it one way there is a recess (normally the pressure side so the pressure pushes the seal out on the OD) and a flat side. The way it came out the side with the recess was pointed up. I see there is some writing on the cover so I wonder if somebody already messed with it and put it in wrong.

Thanks Dan, you've been a lot of help. It was in the right orientation when I took it out. I battled with the snap ring for a while trying to get it in.