915 Transmission Output Flange

86 911 · 86 911's Garage

Hey guys,

I've got a '78 915 trans in my car and I need to replace the output flange seal. I've searched the forums and read the Bentley manual although I cannot find what I'm looking for. I would like to know the size & type of nut that holds the output flange onto the transmission.

Also, the Bentley manual calls for counterholding the flange using a pry bar using two M8 bolts. Is this necessary? Or can I just leave the car in first gear to prevent the flange from moving? If not, can I just use the axle bolts I removed instead of going out any buying the M8 bolts?

This is the first time I'm trying this so I want to be prepared! Thank you for your input!

Flat6pac · 11-07-2015, 02:15 AM

The bolts are 10mm, about 60mm long. When you remove the CV joint put 2 nuts on 2 bolts so things don't fall apart.
It's easier to get 2 bolts at the store than it is to find 2 12.9 cap nuts after you distort them and make them unusable for the closing.
Bruce

gomezoneill · gomezoneill's Garage

10 mm bolt needs a 17mm socket or an 11/16 socket.

86 911 · 86 911's Garage

Thank you for the replies - it definitely helped me prepare for the project. So I got the axle off, flange off, and have been trying to pry out the old seal for an hour now. Going to stop by the store and get a seal puller and hope that does the trick. Luckily, I work the graveyard shift tomorrow so I have most of the day to try to get this done!

gomezoneill · gomezoneill's Garage

Be very cautious that you don't scratch the surrounding area or worse yet break off a part of the transmission. Use a rag and a large screwdriver with a round shaft no need for a seal puller. Work your way around the seal =prying a little at a time.

Jdub · 11-10-2015, 05:54 AM

I agree with caution here, very surprised that the seal is not coming out with just a bit of work (small wooden nail cuticle item from the spouse's toolkit). Are you sure you have ID'd the seal and are not attempting to pull out something permanent?

If you would post a pic we could be sure of this. These seals are so finicky on installation that most folks are told to buy two seals for the first one that might not go in correctly!

86 911 · 86 911's Garage

Hey Guys - it was a success! No amount of prying with a hammer, screwdriver, or pipe wrench worked so I went to Harbor Freight last night and got the seal puller. I placed the seal puller under the lip of the old seal and it popped right out with surprisingly minimal force!!

To install the new seal, I put the new seal in the freezer for several hours (that way it would shrink a little). Then, I applied lithium grease and used a hammer to gently seat each side - worked like a charm and took all but 2 minutes. Highly recommend this approach.