Muncie leak

[Rex T.]

The orignal Muncie M-20 trans in my 64 is leaking grease. Appears to be leaking out the front and running down. Any idea where this may be coming from and how to remedy it? As always, thanks in advance for your help. Rex #8089

[Joel A.]

Re: Muncie leak

Two places for it to leak at the front...
There is no seal at the front, only a very close fit between the nut on the input shaft and the front bearing retainer. If there is excessive wear in this area, or if the unit is overfilled, it can leak here. The bearing retainer itself has a gasket, but it could loosen and leak, too, as well as the four bolts that hold it to the case. They go all the way thru the case, so oil could wick its way out thru the bolts.
The more common place for the leak at the front is the countershaft. It is a press fit into the case, with no sealant. Over time, the shaft will become loose in the case, and oil will seep out of it. You can remove the trans, and smear a thin film of silly-cone sealant over the shaft, and that will fix that laek.

[Joe L.]

Re: Muncie leak

Rex------

The most common sources for this condition are as follows:

1) leakage from a worn/distored cluster gear shaft hole in the front of the case. This is the most common cause. The hole for the cluster gear shaft in the front of the case becomes distorted due to long and/or hard use. Also, if the transmission has been rebuilt many times (and the shaft pressed in and out many times), the hole gets slightly enlarged in the process. Either of these things causes a leak at the shaft/case interface. The only positive, long-term solution for this condition is having the case bushed by an expert. Contact Larry Fischer or Ed Hartnett for this;

2) the threads for the bolts which fasten the front bearing retainer to the main case become worn. Heli-coils or thread-serts repair this problem. Either one should be installed with a good sealer. Using Permatex red (high strength) works best for the thread inserts; this seals and retains the inserts. Use Locktite Pipe Thread sealer with Teflon on the bolts.

[Rex T.]

Re: Muncie leak

Thanks to both of you Joes.................I always know I can count on the NCRS DB for accurate and timely information. Thanks, Rex

[Rex T.]

Re: Muncie leak

Sorry, my resonse should have named Joel and Joe. Thanks to you both. Rex

[David B.]

Re: Muncie leak

Rex,

You can seal the countershaft without removing the transmission. Drop the drive shaft, unbolt the trans from the bellhousing and the trans mount, leave the shift linkage and speedo cable connection intact. Then slide the trans back. It will go back about 1" before interference. This is enough to clean the countershaft with solvent and apply a good sealer. Been there - done that! It works.

David B.

[Mike M.]

Re: Muncie leak

agree with dave. however, i drain the gear oil in the Muncie to a level lower that the cluster gear shaft(siphon it out with a syringe with rubber hose thru the fill plug hole if the Muncie lacks a drain plug). then i wait a day or so before THOUROUGHLY cleaning the Muncie case at the cluster shaft front hole with ether. then wipe a film of Permatex 's The Right Stuff at the case's leak point . then reassemble the Muncie to the bellhousing. got one Muncie with over 15K miles on it and still not leaking. mike