4 Speed Counter Shaft Leak Repair

[Ed S.]

[Joseph L.]

Re: 4 Speed Counter Shaft Leak Repair

A friend and one of our colleagues says a business card is a great seal for this leak. Move the trans just enough to insert the card, and done.
Joe

[Ed S.]

Re: 4 Speed Counter Shaft Leak Repair

A friend and one of our colleagues says a business card is a great seal for this leak. Move the trans just enough to insert the card, and done.
Joe

I was advised to do that ... but a little differently. I was told to apply some sealant to a business or playing card, slide it up so the sealant is on the exposed part of the counter shaft - move the trans forward and then remove the card. The card is used to get the sealant up into that tight area and ensure it completely covers the counter shaft.
I

[Edward B.]

Re: 4 Speed Counter Shaft Leak Repair

My advice is to get it repaired with a bushing. If it's leaking, it's loose. If it's loose, it'll eventually spin. When it spins, you get toast (see picture attached).

And yes, I tried the sealer trick and the card trick. Neither helped me one bit and the transmission had to be scrapped after it grenaded. It would have cost more to rebuild than it was worth (not a numbers matching).

Any competent transmission shop can install the bushing and it's not that expensive. I learned too late.

Ed

[Mike M.]

Re: 4 Speed Counter Shaft Leak Repair

remove muncie, disassemble it, then have machine shop oversize the case to accept the larger muncie cluster gear shaft. have had to do two muncies this way. I was successful with another leaking muncie with the RTV trick but the front of the case and the shaft itself need to be nearly sterile(I use ether repeated multiple times) to remove the 90 wt gear oil as the RTV won't stick worth a poop to oil. mike

[Joe L.]

Re: 4 Speed Counter Shaft Leak Repair

remove muncie, disassemble it, then have machine shop oversize the case to accept the larger muncie cluster gear shaft. have had to do two muncies this way. I was successful with another leaking muncie with the RTV trick but the front of the case and the shaft itself need to be nearly sterile(I use ether repeated multiple times) to remove the 90 wt gear oil as the RTV won't stick worth a poop to oil. mike

Mike-----


If the larger shaft (66-74) is used then the larger ID cluster gear has to be also used. But, this is also an improvement. GM didn't go to the 1" shaft because the 7/8" shaft worked just as well.

[Mike M.]

Re: 4 Speed Counter Shaft Leak Repair

Joe: forgot to mention that. thanks, mike

[Gene M.]

Re: 4 Speed Counter Shaft Leak Repair

Anything less than Mike’s suggestion is just fooling around. To expect an oily surface to seal with any adhesive or sealant...... well you might just as well bark at the moon.

[Ed S.]

Re: 4 Speed Counter Shaft Leak Repair

I can't agree more with Mike's and other's recommendation to pull the trans and have it repaired correctly - i.e., machining and install a 1 inch shaft along with related parts, cluster gear etc. For me, the "RTV" fix is intended to be a temporary solution until I can: 1) find a machine shop in the greater Charlottesville VA area that is competent and familiar with this kind of work, and 2) schedule the work - likely this winter. I find it difficult to find a shop that has the experience and knowledge. All I keep coming up with are AAMCO type shops that have mechanics that were not even born when Muncie manufactured my trans. Thanks again to all that replied.

[Mike M.]

Re: 4 Speed Counter Shaft Leak Repair

ed: any automotive machine shop ought to be capable of boring the aluminum main case. mike

[Ed S.]

Re: 4 Speed Counter Shaft Leak Repair

ed: any automotive machine shop ought to be capable of boring the aluminum main case. mike

Thanks Mike - I have "feelers" out to the my local Charlottesville "gear heads" for recommendations - hopefully, I will get a few good ones.

[Edward J.]

Re: 4 Speed Counter Shaft Leak Repair

Thanks Mike - I have "feelers" out to the my local Charlottesville "gear heads" for recommendations - hopefully, I will get a few good ones.

Ed, Theres aways the possiblity that a machine could screw something up, the shaft is a friction fit, I worked for a GM Chevrolet dealership for many years as a tech and they leaked back then when under warranty and they can still leak with the wrong guy fixing this. its a one time only repair if its leaks again its a new case. The general never really sealed a engine or transmission very well in the 60s or 70s. Your ideal to fix with sealant worth the try any oil in the area should be cleaned first.

[Ed S.]

Re: 4 Speed Counter Shaft Leak Repair

Lot of great advice. I don't abuse this car so I am not terribly concerned about twisting the innards of the transmission with a slightly loose counter shaft. Of course that doesn't mean it will just decide to rapidly disassemble on its own some day just to show its age. I am definitely going to do the RTV application - if it holds, well..... all the better. If not, decision time. It does not "leak" badly, more like a very slow drip - I can live with that (almost)..... as I am very much like the rest of us.... we want it to be right. Not rushing into this by any means. Thanks again to all - and Ed, you raise an excellent point.

[Joe L.]

Re: 4 Speed Counter Shaft Leak Repair

By the way, replacement main cases for Muncie transmissions are available as manufactured by Autogear of Syracuse, NY. While not exactly correct in configuration, these cases are superior to the originals in many ways. They are available in both 7/8" and 1" cluster shaft size. If exact correctness is not an issue, I think they are a very good way to go. Autogear also offers steel rear main bearing retainer plates and improved extension housings.

With respect to the rear bearing retainer plate, there is a usage-induced deficiency that's often overlooked. After extended use and especially if a transmission has been abused during its life, the 4 bolt holes become slightly elongated. This is often missed when folks inspect the plate after transmission disassembly. Despite the belief by many that these plates are not a wear part, elongation of the holes, even slightly, renders the plate not suitable for re-use. I suppose while it might be possible to bush the holes, the best solution is a new plate.

[Frank D.]

Re: 4 Speed Counter Shaft Leak Repair

Lot of great advice. I don't abuse this car so I am not terribly concerned about twisting the innards of the transmission with a slightly loose counter shaft. Of course that doesn't mean it will just decide to rapidly disassemble on its own some day just to show its age. I am definitely going to do the RTV application - if it holds, well..... all the better. If not, decision time. It does not "leak" badly, more like a very slow drip - I can live with that (almost)..... as I am very much like the rest of us.... we want it to be right. Not rushing into this by any means. Thanks again to all - and Ed, you raise an excellent point.

I did the RTV "fix" on my May 63 very early Muncie...I pulled the transmission back an inch or so and cleaned the area repeatedly with lacquer thinner. I used the black Ultra RTV along with a super thin piece of flexible rubber cut in a square (don't remember where I got it); prob thinner than most gaskets. Put the square over the countershaft hole coated in RTV and bolted the transmission back up and let things cure overnight.
Yeah - everybody said the transmission would be "cocked" because of the rubber and cause the polar ice caps to melt... Never happened and the transmission works superbly still..

That was in 2015 and its never leaked again and I drive the car a lot, 5,000-6,000 miles/year. Yes, I know its not a permanent fix and doesn't really address the wear on the parts - I intend to straighten it out someday, just haven't gotten to it...

But now, I have a differential cover starting to leak, which I'll fix next week - that sucks because I had the rear nearly completely apart replacing all the rubber and I and a friend rebuilt the trailing arms...last summer.