BK N 66

i know this post probably has been beat to death.

but, does anyone have a muncie 4-spd that does not leak or drip
trans fluid??? i have never seen or heard of one that did not leak
fluid sooner or later?? i heard that the reason is that they never
used any type of seal on the back shaft? even when thes muncies
are rebuilt you can put silicone sealer around the shaft but iut only lasts
for a while and then starts to leak??? u would think that they would have used some kind of seal for these transmissions but i gues they
were old school and the technology wasnt that good?? any comments or opinions on these old muncies. they are old school but they sure
were and are good old transmissions. i just wish my muncie didnt
drip fluid????

knight37128

Mine doesn't drip fluid.

Gear oil is so thick that it doesn't "drip".

66jack

if your tired of that drip...i'll take it off of your hands..

jack

GCD1962

Nope, not a drop leaks out of mine

Dan Hampton

If you are referring to the tail shaft (back shaft) there is a seal. Is that where you leak has originated? It is not characteristic for a Muncie to leak. Put together properly they most never leak. The problem is that novice rebuilders do not put them together properly, disregarding the fact that mating surfaces have to be flat (a simple file will do). Also, the counter bore hole is often never addressed or, if it is, some think that a spot of JB weld will cure the out-of-round problem and this can be a source of another leak. The bearing retaining cover's bolts do not thread into a blind hole and if you don't use silicon on each bolt that, too, can be another source of a leak.

Chuck72

I just went through mine and put in new bearings, seals, gaskets, and a new countershaft (the old "while I'm at it" disease). The new countershaft was a nice snug fit into the front bore. I really do not see how any gear oil could possibly leak out the front countershaft bore, but I ran a small ring of silicone around that area. No leaks.
Regards,
Chuck

SPLITRAY

ditto

midyearvette

...great post....if you have a leaky rear seal, chances are very good that the rear bushing and or the yoke are worn past tolerances...also the welch plug could be leaking in the yoke....just a thought....the only leaks i ever encountered were in that area and also the fork seals sometimes....jmo..good luck....

MikeM

I have a half dozen of them. None leak. None have ever been apart that I know of and none of them have been beat to death.

fwillison

my muncie leaks, relatively small amount, but several drops are on the floor after sitting for a few days. When I crawled under to do some exhuast work I looked at it. Hard to tell where it's coming from, but the plate and shift forks seem to be wet with oil more than elsewhere.

BK N 66

what gear oil do u use and what weight is it?? i use redline
90 wt gear oil. and it drips from the flat bottom of the tranny??

BK N 66

what brand of gear oil and what weight are u using in your tranny??

i use redline 90 wt gear oil and it drips a little bit???

Dan Hampton

Using Redline 90wt is not going to be the reason for the leak. You need to remove it from the car, examine it, and find the cause.

xiaoman

mine either.
regards,xiaoman

midyearvette

where is the leak??.. ie.speedo o ring?

Astrodokk

Mine leaks from the front countershaft bore. Tried the gasket seal fix found on this forum but it still leaks...it's only a drop every few days, but I don't like having to wipe the floor!

DZAUTO

If you have a Muncie (or an alum B-W T-10) that leaks from the front cluster gear shaft hole, INSTALLING A MADE-UP GASKET OR USING SOME KIND OF SEALER (RTV, JB WELD, etc), WILL NOT, REPEAT, WILL NOT FIX THE CAUSE OF THE LEAK!!!!
If it leaks at that hole, the reason for the leak is that the hole has become enlarged as a result of many miles, abuse, extended high rpm's in the gears, etc. The nose of the shaft as well as the hole in the case are a very slight taper fit. Thus, when driven into the hole, the shaft makes a tight seal (that's what it's supposed to do). With time/miles/abuse, this hole becomes enlarged, the shaft loosens and begins to wobble, and as the hole enlarges and the front of the shaft begins to wobble around the hole, this contributes even more to the enlargement of the hole. Thus, a leak!!!
Covering the hole with a gasket or sealer is only a STOP GAP fix. As I said above, IT DOES NOT ELIMINATE THE CAUSE OF THE LEAK!!!!!
Sooooooooooooooo, how does one go about fixing the cause??? Remove the tranny, TOTALLY disassemble it (yep, the cluster has to come out also) and have the hole repaired (or buy a new Auto Gear case).
Once the hole is returned to the correct size, and then the cluster shaft is installed, the front of the shaft SHOULD BE BELOW the front face of the case!!! If the front of the shaft protrudes beyond the front of the tranny case, then when it is installed against the bell housing, the shaft will be pushed back into the tranny, and the leak will return.

Tom Parsons

Astrodokk

Yeah, I know. That's why it still leaks, I didn't want to go through all that to repair it correctly.
Mechron told me all about it when I had it out, but I decided to leave it as is because I wanted to get things together fast for the drag race season. It would probably happen again the way I drive it.

BK N 66

yes i know the cause of the leak. it is leaking from the countershaft
pin. same as all muncie leaks. they never used and seals or
gaskets for the countershaft pin. when the tranny gets hot it leaks from the countershaft pin. i was told when it was rebuilt about a year ago it would eventually leak from the countershaft pin.

i dont know if it can be fixed without removing it from the car???

i was also told it could be fixed temporarily but it would eventually
start dripping again??

any opinions or comments. i run redline 90 weight tranny fluid.

transmission shifts great and works perfectly. when it was rebuilt it
had all new syncro gears and all new cluster gears.

i just wish it would drip fluid. i know its only a few drops but it is
annoying. my friend said not worry about and just drive the car.

he said his trannhy does the same it drips. what do u guys think???


thanks

DZAUTO

Well, since I've been rebuilding 4spds (mostly Muncies) for 40+yrs, I fix my own. Properly repaired, they don't leak unless they get LOTS of abuse!

Tom Parsons