Help diagnosing 915 leak

[sigchuck]

Hi guys, I have the engine and transmission dropped from my car and have what appears to be a leak from my transmission.

I'm not sure that it was an active leak as I never noticed any fluid, but the crossmember did catch quite a bit as well. Any thoughts? It looks like it could have been coming out around the brass "plug", but not certain.

This is from my 83 US spec SC if that makes a difference. Thanks for the help!

[yelcab1]

There is a seal there, inside the gearbox. Do you feel lucky today?

[proporsche]

as yelcab said there is O ring on this shaft....

[Ian Comerford]

I guess that as the leak is above the fill plug you will never lose much fluid, it will always be a seep or a weep. Change the oils every two years or so and it will be fine.

[sigchuck]

So maybe best to leave alone until I need new synchros, etc.?

[Ian Comerford]

I could be wrong but I don’t think you can lose substantial enough quantities of fluid to cause a problem. Check or change the gearbox oil slightly more regularly than normal, maybe every two years

[Zuffenwerker]

Since the transmission is out you might as well fix it. You will need the o-ring that fits the reverse idler shaft, shift shaft seal, and rear cover paper gasket. It will take you at least an hour to replace all three.
Well worth the hour just pop off the cover and reseal it. When you pull off the cover the reverse idler thrust washer usually falls out. Just put it back on the revers idler shaft making sure to face it the same way it came off.

Daniel

[yelcab1]

The problem with opening a 915 gearbox is ... you can't stop at just that. You want to do the 1st and 2nd synchros, maybe slider. Then you have to go deeper and find that the bearing race is spinning and then it all goes to hell in a hand basket. $5,000 later, you might be done. Fix it all or leave it but don't do it half ass.

If the rest of the car is leaking oil, you might as well leave this one alone.

[pmax]

Why wouldn’t you replace a leaking o-ring ?

Having said that, the leak says nothing about the condition of the synchros etc. so the slippery slope isn’t a given.

[sigchuck]

Thanks, guys - I’ll give it a try. I read first couple posts to indicate the juice wasn’t worth the squeeze. If popping off the nose cone is as easy as it looks, I’ll give it a try.

I imagine locating the paper gasket is easy enough, but what’s the name of the rod that needs the o-ring? The transmission otherwise shifts fine, so not too concerned about while-you’re-in-there-itis.

[Zuffenwerker]

999 701 169 40
Thats the part # for the leaking O-ring its on the shaft for reverse idler gear.

Definitely not a half ass fix, takes about an hour...fixes a leak...job well done. Just about the only while your in there is the small radial seal for the shift shaft. Synchros are so far away from what this job is your basically not even "in there"

doo gooders remember no good deed goes unpunished

Daniel

[snbush67]

That’s the friendliest leak one could ever wish for. Wipe it off and walk away.