# Muncie oil leak



## old-goat (Jul 10, 2011)

My M-20 in my '65 is leaking out the front at the input shaft area some place - is there a seal in the front bearing retainer? I don't see one in the parts breakdown I have.


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## geeteeohguy (Feb 2, 2008)

They usually leak out of the idler shaft hole when the case gets worn. There is no gasket or seal. There is no seal on the front bearing retainer, either. Just a gasket. My bet is that it's the idler shaft hole. You can remove the trans and apply a ring of silicone sealer to the bellhousing and bolt it back up, or you can get a new transmission case or have yours repaired. $$$. Or,if it's a few drops, live with it. Most of these early Muncies seep a bit out of the idler shaft hole.


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## old-goat (Jul 10, 2011)

geeteeohguy said:


> They usually leak out of the idler shaft hole when the case gets worn. There is no gasket or seal. There is no seal on the front bearing retainer, either. Just a gasket. My bet is that it's the idler shaft hole. You can remove the trans and apply a ring of silicone sealer to the bellhousing and bolt it back up, or you can get a new transmission case or have yours repaired. $$$. Or,if it's a few drops, live with it. Most of these early Muncies seep a bit out of the idler shaft hole.


 Thanks for the information, that isn't something I even considered. I need to pull the trans any way to deal with some clutch chatter so I will check the case


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## geeteeohguy (Feb 2, 2008)

Yes, my money's on the countershaft hole. Most of these trannies leak a bit here after 45 years or so! The fix is to bore the hole oversize and install a bronze bushing. It's a job for the machine shop. That, or get a new case. Me, I'd draw a circle of sealer around the hole, let it set up for about ten minutes, and stab the trans back in. The issue is that the hardened steel countershaft uses the soft aluminum case as a bearing. Over time, it simply wears oversize a bit. My '65 will leave about a teaspoon of gear oil on the floor if it's parked for a few months. Been doing this for 30 years or so. I have no plans to fix it until it needs a clutch....and that won't be anytime soon, if the present clutch (installed in 1984) is any indication!!


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## ALKYGTO (Mar 29, 2010)

Plus it's not a Pontiac if it's not leaking _something_......


Flamesuit on! :shutme


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## leeklm (Mar 11, 2012)

Like geetee said, the press fit counter shaft is likely the cause. I am now installing an aftermarket "super case", which has a thicker front/bearing surface. Since it is thicker, it leaves a space between the front surface (which of course mates against the bell housing) and the press-fit shaft. It comes with an aluminum plug that is squished into place when the trans is mounted, and should stop my front leak... If you ever need to do something with yours, I highly recommend the new super duty case, which is supposed to add a fair amount of strength, and is somewhat reasonable in cost. (all relative in this hobby)


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## geeteeohguy (Feb 2, 2008)

The super case, as well as being superior to the original case, is a sure fire way to end this leakage problem.


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