Another Fluid Leak

About 3 weeks ago, the Javelin developed a transmission fluid leak around the pan, and the shop replaced the pan gasket. Drove the Javelin 2-3 times with no leaks.

    I've seen that same leak and it turned out that the speedo cable was installed incorrectly along with the wrong O-ring.

I would be looking at the speedometer cable, or the shift shaft seal.

dltowers wrote: The thing I cannot figure out is why it takes several days for the leak to start?

Because cars had "Gremlins" LONG before AMC did.

I have had an oil leak on the 727 trans on the Jav for a few years now, just one or two spots, but in the last year it has got progressively worse. I have had sheets of cardboard under the car to act as sponges, and after a few weeks they were sodden. So much leaked out the car would not drive properly due to lack of fluid. I was guessing at the dipstick tube, as there is an “O” ring on the tube which seals it in the body. Next guess was a leaking pan gasket.
So, get the car up high enough to see properly and there’s oil all over the pan, and the edges of the gasket are soaked all the way round. Checking the dipstick entry it’s all dry, so that shows the “O” ring on the dipstick tube is OK. I slowly dropped the pan to allow what was left of the fluid to drain out. Check out the filter while we’re there, and it’s all good.
Clean everything up, check the pan for warped sides and flat flanges, all OK. New gasket, bolt up and refill. Job done.
Check two hours later, it’s leaking ! What the ! It appears to be at the rear of the pan. Wipe down carefully and watch. It’s not the pan at all, but coming out higher up from the body. A very close check revealed that it was leaking from a pin which is pushed through the body. Looking in the parts book, the pin, which is about 3/8” diameter, holds the reverse band lever in place.
Now in their wisdom, to prevent that pin falling out backwards, the rear extension housing has been cast with a little tang (or ‘finger’) in it that covers the pin. The manual doesn’t give any clues on how to replace the O-ring; it just presumes you’ll change it when the trans is out for a full rebuild. The question is: can that pin be pushed out far enough to get to the O-ring groove without something falling off inside ?
There appears to be no pressure around the pin, it’s only gravity flow allowing the leak. So, off with the pan again and drain the fluid. If I couldn’t change the O-ring then my fall back position would be to find some oil resistant epoxy and smother the pin on the outside, and hope it held the fluid in.
Once the pan was off, I took off the filter, held on with three screws. With that off, I could see up inside above the valve body to the other end of the pin, and it looked like the pin was long enough to be able to push it out slightly without it falling out. There is also no pressure on the reverse band which was a relief too.
I got half a hacksaw blade and cut off the tang on the housing so the pin would be able to be pushed out partially. This was not easy, due to the cramped position. (I would make up a clamp later, to replicate the tang).
Then, pushing from the inside out, I carefully exposed enough pin to see the O-ring. You can get a long screwdriver and push it through above the valve body; there’s just enough room. Once exposed, and using an O-ring pick, I was able to get the O-ring off. It was flattened out and had gone hard. I have an odd selection of O-rings and luckily managed to find one that matched. It was a BS-014. It went on easily and with a bit of O-ring grease tapped it back into the housing. It was a tight fit and needed a bit of a tap with a hammer. This confirmed it was a tight seal.
To replicate the tang to stop the pin falling out. I got a short piece of flat bar, bent it 90° and drilled a hole for the bolt holding the rear extension housing.
Why does it leak after a few days ? Because the torque converter drains back slowly, and raises the level of fluid in the trans body.







Edited by 74gremx - Sep/07/2014 at 6:43am