tranny fluid leak

1bar · 07-29-2002, 09:17 PM

Rolling home on a really nice cruise, everything's running perfect again after the last $%^& CIS repair, life's great, right? Pull into the garage and as I'm walking into the house I look back and ... Hey, is that oil on the floor? Hey, is that oil all over the driveway? WTF?

Yes, it's oily - but it turns out it's gear fluid (blue Swepco, definitely not engine oil). It's leaking out from where the engine bolts to the transmission - all around the flywheel. As it sits still, the oil flow has stopped, so it's not some sort of major crack in the case.

Any ideas? Is there a seal around the transmission input shaft that might have given up the ghost? Everyone always talks about the seal on the flywheel end of the crankshaft (I repalced that one the last time I had the engine out) - should I have looked forward to the transmission? Should I be bummed?

Larry

marcesq · marcesq's Garage

Larry:

Is there oil on top of the tranny case?? If so, I think that the 915 has a breather of sorts on top, which could expel oil if you somehow managed to over fill.

If not, sounds like the main seal on the output shaft of the 915 gave up the ghost. Any idea when it was last replaced?? Replacing the seal is a PITA.

In any event it looks like you are in for an engine drop BBQ. Replace Guide Tube & O-ring while you are in there.

Good luck.

scphelps1 · scphelps1's Garage

This vent on top of the transmission that Marc mentions was the source of my leak. Jim Sims let me know that the vent must vent to the front 90 degrees of the car or it will blow oil out. As I filled the transmission via the vent, I had not paid attention to the orientation of this. With the engine in the car, it is not very easy to get to it, but you can reach up and feel where the hole is and ensure it is in the proper orientation.

Jim Sims · 07:52 AM

Larry, It seems from your description that the transmission input shaft seal has failed. If you keep driving there is a chance you will "oil your clutch" and it will begin slipping. Changing these seals varies in difficulty. They are in the guide tube. On some years (guide tube pressed into housing and bored for seal from different directions) they can be only replaced by disassembling the transmission to gain access to the inside of the differential housing. Other years they can be extracted from the clutch side using a special tool and starting sometime around the 1976 models the guide tube can be removed and the input shaft seal "easily" replaced along with the guide tube if worn (clutch release bearing slides on the outside of the guide tube) and its sealing o-ring as Marc mnetions. Engine and tranmsission will have to be dropped and transmission separated in all cases. You may have to replace clutch disk if it has become oiled. Good luck, Jim

1bar · 07-30-2002, 08:30 AM

Sorry, guys - I should have mentioned that this is a 930 4-speed transmission in a '77 Turbo. The oil is definitely coming from around the flywheel - it leaks out the openings (where you can see the starter ring teeth), and has definitely spun around the flywheel. I'm sure the clutch is saturated.

Jim Sims · 07-30-2002, 08:36 AM

Well the good news is you don't have to take the transmission apart. To remove the guide tube all one needs is a screw driver, a piece of wire to make a "bail" (there are two holes in the end of the guide tube to hook the bail into) and bar to lift on the bail and a piece of wood to keep the bar from marring the edge of the bell housing. Bad news is you have an engine drop and clutch disk replacement coming up. Jim

1bar · 07-30-2002, 10:40 AM

Jim, this is really good news. I've pulled this engine off and on enough that I'm actually getting pretty good at it! Any chance that I don't have to crack the tranny open makes me feel much better. I'll check out the clutch alternatives and let you guys what I find when I get in there.

Larry