Transmission Fluid Leak...towards the front of the car.

[rennch]

I've got a 69 911T, with a 915 tranny from a 72, mated to a 3.0 Liter from a 79SC. At the moment, I'm leaking a considerable amount of transmission fluid from the front of the transmission. It wasn't really doing this before, and it hasn't really been driven since the engine swap. Thoughts?

[Oh Haha]

It could be the shift rod seal or the shift fork cover. Both are notorious for leaking. Both can be repaired easily, thank goodness. Do a search here for tips on replacing the shift rod seal in the car. It is tricky but doable. The shift fork cover is a simple paper gasket. You can make your own or buy a factory gasket. You will lose some fluid when you remove the cover so be prepared to refill a little.

[Matt Monson]

It could also be the output shaft seal. The bummer is that if that's it, on a '72 there is no removeable guide tube and the tranny has to come apart to properly fix the seal. Back when I worked for Carquip, they had a little seal from some other application that they would press in from the front on those trannies. It was really a hit and miss proposition. It worked about 50% of the time and 50% of the time the tranny had to come apart.

[Christien]

I just went through this entire ordeal, right down to a full-on rebuild.

I talked to a mechanic at a well-respected local shop who's been working on Porsches for 30 years. He said 80% of 915 tranny leaks come from the shift fork seal, which is really good news for you, because all you need to do is drain the tranny, pull off the cover (4 13mm nuts), replace the gasket and close her back up.

He also said paper gaskets for old engines/trannies like ours are useless. They don't bother with them any more. He said machining techniques in the 70s were far from precise, and today's modern liquid gaskets make a far superior seal. His first choice is Threebond 1280B, which is a bit hard to find, at least around here (threebond.com). His second choices, which are easy to find, are Permatex "The Right Stuff" and Permatex Motoseal.

Definitely try the easy stuff first, before you pull the engine and tranny!

[rennch]

Thanks guys...I'll try to track it down today. I'm heading to paint next week, so I need to wrap this mechanical stuff up asap.

Matt...you should come by and check it out sometime.

[rennch]

Hey guys...I have to move this car a few times before I'm going to be able to get this seal in. What can I put in the tranny (that I know will leak out) to make sure its protected in the interim?

I don't want to put $wepco in just yet. It's got Swepco blue in it now.


TIA,

mike

[dweymer]

I have a leak at my speedo drive seal, could be that?