Frankie the Fink

OK... I'm trying to fix my last leak at the front shaft in the situation in the subject line. I'm not a tranny guy and have no clue what I'm looking at here. This will be the RTV/gasket stopgap fix and I'm not pulling the tranny OR engine so let's get past that right now.

This picture is straight up at the tranny with the bellhousing at the top and tranny at the bottom. Its been thoroughly cleaned with lacquer thinner and ready for the RTV/gasket. What am I trying to seal ???

Am I just going around the 4" diameter of the round thing on the tranny with the bolts in it ?? Is that the source of the leak ?? If the leak is closer in to the front shaft then I don't see how that helps as things will just leak into the bellhousing in that case and leak from there.

I expected to find a splined shaft that I would encircle with RTV and the tranny is back as far as it will go ... the Hurst shifter is butted up against the tunnel in the back...so what you see is what I got to work with...

kingwoodvette

On mine the leak was from the dime sized shaft in the lower portion of the tranny in your pic. Sealant was skimmed over the entire shaft end. Seems to have stopped my leak-at least for the time being. My understanding is there is no seal on this shaft. There may be other ideas out there.

Frankie the Fink

I made a variation of this gasket (which will be coated in Ultra Black RTV) that another forum member uses. I just made the round part the same size as his shown here. Is that sufficient to stop the leak ??

Frankie the Fink

Are you telling me its this little hole at the red arrow (that seems to have a the end of a shaft or freeze plug like thingee in it) is the source of all this grief ??

Chuck Gongloff

The "thing" with 4 bolts in it is the front bearing retainer. Under it is the front bearing. The round gizmo is the countershaft.

The leak most likely is coming from the front bearing.

64roadster

MikeM

There is NO seal on the front bearing. There is a paper gasket behind the bearing retainer. The front bearing drains oil back into the front of the case and the bearing retainer.

In all likelyhood, the leak is coming from the cluster gear countershaft which is pretty common on worn transmissions. Slap some Permatex Form A Gasket over the end of the shaft as previously suggested by Kingwood and bolt it back together. If it still leaks, you have two options. One is to pull the transmission and fix it correctly OR you can keep a piece of cardboard under your car to keep the grease off your garage floor.

It is encouraging to see you getting a little Bubba' in your act.

69z28&ss396

Frankie,

Bailing you out seems to be getting to be a fulltime job! Anyway, here goes.

The input shaft, which is fourth gear, has a reverse thread lock nut in it, that when spun in engine rotation, pulls gear lube back into a channel that drains back into the case. There is a gasket right behind the bearing retainer. Those usually don't leak unless they are really old. the source of the leak is probably the countershaft that the cluster gear rides on. The early 63-65 trannies with the 7/8" shaft are notorious for doing this. if you do opt to fix this right, you will need to have the case drilled and a proper bronze bushing installed. This warrants complete disassembly of the tranny. Not the direction you want to go, but I can offer a temporary fix that I have used. If you get something called "Honda bond" you can use that to cover the countershaft and then that will stem the flow. Honda bond is the absolute best RTV I have ever used. Ive used it on all my projects for sealing and that stuff really holds up. Its the same sealant used in Honda's F1 team cars. You can get it at any local Honda dealer or order it online from just about any place if you Google Honda bond. That gasket you made wont work unless you cut the top off. How else are you going to get it around the retainer and input shaft? Good luck buddy. PM or ring me if you have any issues or questions.

MrTrim

Having built, repaired, destroyed or otherwise played with many Muncies in my lifetime, more likely than not, your leak is coming from the countershaft pin.(the small "thingie" in your picture) the pin is a zero fit into the case with no seal. In theory the aluminum case will heat up and seal the pin from leaking under use and be zero at cold temps and not leak when cold. That's the theory anyway. In reality, the hole will oblong up and down due to the pressure against the countershaft from the mainshaft during normal operation. This is what causes the transmission to leak oil from the pin hole. This is assuming that the input shaft, bearing and retainer is correctly assembled. I personally have broken transmission cases at this point in my race cars, due to the pressures of high RPM shifts. You can try some sealer art the pin location but if the pin rotates in the case, as it will if loose, the sealer will only be a temperary repair. The only true fix is a new case and countershaft pin. Although I have heard stories of people re-boring the case and adding a tighter bushing of some sort. But I have not personally seen this done. Hope this helps. There may be other ideas out there, but this has been my experience with these transmissions.
Chris

MikeM

Bubba's are everywhere! Behind every bush!

69z28&ss396

You ask Bubba questions, you get Bubba answers..

Frankie the Fink

So the thing at the red arrow in my pic in post #4 is what is leaking and that is the countershaft?

DZAUTO

That is the MOST COMMON source of a leak on a Muncie. You can almost count on it as the source if a Muncie is leaking from the front.

69z28&ss396

Like DZ said, that's probably the leak..

kingwoodvette

Frankie, sorry I have been away. Yes, as many others has said the little thingie behind the red arrow was what I was talking about.

KC John

This is Bubba, but it works like a charm. Take some thin rubber, like the stuff you put behind cement board in a shower. Add some Black silicone to the trans case and the patch so that the rubber is sandwiched between the RTV. Stick that over the counter shaft and bolt the trans back up. I did this to mine a few years ago and mine no longer leaks at that point. I still have other leaks to fix, but that one is gone.

Frankie the Fink

Ok - back from dinner with the wife in the '61 ('Ole Reliable') and dug into my '64 Corvette Shop Manual and edumicated myself on crossshafts. It indeed is not the greatest design and is not doubt my leak (and of course once Tom Parsons says something is so - you can take that to the bank). Interestingly enough in the "Troubleshooting" section of the manual it states the solution for a leaking crossshaft...e.g. "Replace Case".

I'll do the RTV thing in the morning and see how it goes...thanks to all and particularly Tony who babysat me through my shifter shaft lip seal repair...

vintagecorvette

If you want to do the job correctly then Scotty at Garage Motorsports in Vancouver Washington can bush your original case.

1103 W McLoughlin Blvd, Vancouver, WA 98660
(360) 735-0753

Or you can punch the 7/8 pin out the an 1" pin and change the cluster.

Frankie the Fink

I started this thread off stating that I'm trying to avoid pulling the tranny although I know that is the best way to do the fix.

If I go for that later on then there is a great Muncie guy here locally that rebuilt the one in my '67 Chevelle if I ever get around to pulling this one out for a leak fix and overhaul...but thanks for the referral.

GCD1962

Save a lot of time, sweat, and aggrivation. Buy a new case from Autogear which has improvements on the leaking countershaft problem, plus other improvements. Don't waste time and money on trying to repair your case.