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Fix for leaky Muncie

Posted: Sat Apr 12, 2025 4:04 pm
by Dennis Prince
Howdy, My friend had a Muncie that was leaking badly from the shift rails. I built covers for the rail ends and it has stopped the leak. I used 3/4 in conduit and the plugs out of a metal electrical outlet box, burned off the galvanize with battery acid and welded together and welded to a piece of strap that was drilled to allow rails to pass through, welded the tubes to the strap (two are longer than the others) then drilled and tapped the trans top with 1/4-20 and used allen head bolts. I needed to clean up the casting on the top so that the sealed could seal it up. I then coated the shift shafts with grease so the sealer wouldn't stick to them and assembled.
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Re: Fix for leaky Muncie

Posted: Sat Apr 12, 2025 10:01 pm
by Erik Barrett
These things want very thick lube. 90wt won’t cut it. Use the 600W from the vendors or put in a bottle of STP or similar product and top off with 85/140 gear lube. This helps with three issues. It’s less prone to leakage, makes shifting easier, and cuts down on the noise Muncies are known for. May help if you want to have a conversation while in overdrive.

Re: Fix for leaky Muncie

Posted: Sun Apr 13, 2025 12:45 am
by Dennis Prince
Running straight Lucas (STP equivalent) it still leaked badly before.

Re: Fix for leaky Muncie

Posted: Sun Apr 13, 2025 3:05 am
by Erik Barrett
Well then it would seem that your solution is a good one.

Re: Fix for leaky Muncie

Posted: Mon Apr 14, 2025 3:05 pm
by Craig Leach
Hi Dennis,
I have had this discussion with a gentleman that did this very same thing with poor results. After running some time it became very hard to
shift because the cups filled up with gear oil & stopped the shafts from moving. His solution was to have a tube that allowed the oil to return
through the other shaft. I'm sure he will chime in with more detail when he sees this post. My solution was to make a gasket that has as small
of a hole for the shift forks as can be installed, to prevent as much oil from getting to the shift rails as possible without keeping lube from
them. This doesn't make a Muncie leak free but does cut it down quite a bit & slows the oil seeping out the shifter @ the top. I find trying to
stop every oil leak in a T is like wrestling in the mud with a pig. Eventually you conclude it is a waste of time & the pig is enjoying it.
Craig.