Rear trans seal flange stuck

[Beej '86 325es]

The dealer is replacing the rear transmission seal for me. They literally gave up today. They tried both a high powered impact wrench and a breaker bar with a 6 foot cheater pipe and couldn't get the rear flange off.

Is there a trick to this???:(

[jlevie]

I've found that judicious use of an oxy-acetylene torch on the nut works wonders.

[Beej '86 325es]

any risk of damaging anything with that heat?

Thnaks!

[JGood]

any risk of damaging anything with that heat?

Thnaks!

Keep the heat on the nut itself. You could probably melt the seal after a while, but you're replacing it. Heat + impact has always worked for me. I don't mean a little girly impact either, I mean a big badass impact gun with lots of power.

Good luck with the seal. Nobody I know has replaced one with good results. All 3 of mine have leaked worse after replacement, along with the 2 I've done for friends. There's some special tip for this that people don't share, apparently.

[jlevie]

The "magic" w/respect to the rear seal is that it must be driven in square with the right sized driver and that if there is any grooving on the flange the seal must be seated in a different position or the flange replaced. If I see wear on the flange, a new OE part goes in. I've never had a replacement seal leak, yet.

[Beej '86 325es]

Thanks guys - they are using a 600 ft/lb or in/lb impact wrench (not sure of the units on those things). They were hesitant to use heat, but I'll give them a call and have them try that.

[JGood]

Thanks guys - they are using a 600 ft/lb or in/lb impact wrench (not sure of the units on those things). They were hesitant to use heat, but I'll give them a call and have them try that.

This is coming from a dealer? I'd pick the car up and go to another dealer. They should know what they can and can't do.

[JGood]

The "magic" w/respect to the rear seal is that it must be driven in square with the right sized driver and that if there is any grooving on the flange the seal must be seated in a different position or the flange replaced. If I see wear on the flange, a new OE part goes in. I've never had a replacement seal leak, yet.

I didn't notice any unusual wear on my flanges. I didn't spec it out with a micrometer though. I used new seals each time, and pushed it in as straight as possible. All but one went it with hand pressure. The one that didn't leaked profusely afterwords (obviously).

I tried seals from the dealer, and various aftermarket companies. I heard there is a special grease you are supposed to use on the splines as well...

[DJB]

The dealer should know that the transmission output shaft flange must be installed in with a high-strength thread sealant on the splines and threads -- the type that will only release with the application of heat.

I bent a steel bar bolted to the flange and was at the limit of a 5' pipe on a breaker bar before I gave up that approach. I even bought a new impact wrench.

But 10 seconds or so with a MAPP torch and the nut spun right off with the impact wrench. I wasn't even expecting it to work -- it was just a practice run to see that I could switch from torch to wrench without having the transmission fall over.

[Naplm00]

Yep,

I used Mapp gas and a cheapo 1/2in husky 350 LB# impact. I used a thin wall GM oil pressure sensor socket to remove it.

Heated the litearl shit out of it, then zipped it off.


I used hylomar racing blue to reseal the new seal and new nut that i put in place.


EDIT::

and i did this on my back with the car on jackstands

[Beej '86 325es]

Thanks for the reassurance guys. The dealership is still sitting on it, but I'll let you know what happens.

[Beej '86 325es]

The dealer had no luck guys. I may be replacing the transmission.

[KillaCam]

try a air chisel
it fixes everything