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Engine oil inside Trans underpan

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Old 02-20-2018, 09:31 PM
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M Pete
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Default Engine oil inside Trans underpan

Hi all,

I was replacing my starter on my 1980 auto transmission car do day and was looking at the many leaks while I had it up in the air. The starter was covered in greasy grime! There is usually a drip of oil hanging out on the drain plug and the underpan just behind it. As a a newbie to these cars & engines I did not realize that there was actually a hole in the bottom of the underpan. I wiped away the hanging drip of oil from the underpan and quite a bit came out of what I found out was the hole. I had thought that the oil was coming from an old oil pan gasket or the drain plug. Now with oil INSIDE the bell housing/underpan I would think that I need to replace my rear main seal as well? Am I correct in my thinking? I may as well replace both RMS a oil pan gasket while I'm at it.

This will be priority #3 after stoping my power steering and brake caliper fountains. I would just like this thing to stop spewing fluids in my garage!!
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Old 02-21-2018, 04:11 AM
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riverracer au
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corvette's don't leak, they just mark their territory
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Old 02-21-2018, 07:33 AM
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Mine is known everywhere!!!!!
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Old 02-21-2018, 07:40 AM
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The underpan you are refering to is merely a dustcover / stone guard for the torque convertor with a weep hole. The question is, what color are the drops coming out? If redish then its likely the front seal on the tranny pump. If its brownish oil, then its likely the rear main seal on the block. Four small bolts and that cover drops down for a closer inspection.

Not too bad a job replacing rear main seal. Many suggestions on this forum. Of course the pan, oil pump and main bearing will have to come out. To drop the pan the idler arms two bolts will have to be removed so the steering linkage drops down for pan clearance. When you install a new rear seal, always "clock it" so the seal gaps are at 8 o clock & 2 o clock instead of lining up with the pan gap (3 oclock & 9 oclock).

A oil soaked starter is likely from the valvecover gaskets, simple fix.
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Old 02-21-2018, 08:23 AM
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M Pete
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Originally Posted by riverracer au View Post
corvette's don't leak, they just mark their territory
This one owns the $hit out of my garage then.
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Old 02-21-2018, 08:27 AM
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Originally Posted by HeadsU.P. View Post
If its brownish oil, then its likely the rear main seal on the block. Four small bolts and that cover drops down for a closer inspection.


A oil soaked starter is likely from the valvecover gaskets, simple fix.
It's engine oil for sure. Thanks for the confirmation.

I actually had the valve cover gaskets replaced a little while ago While it was in the shop, so you are spot on!
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Old 02-21-2018, 09:34 AM
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stingr69
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Oil leaking from anywhere will make you think it is the rear main seal or oil pan. Degrease the engine well and hit it with talcum powder then drive for a few miles to see exactly where the oil is actually leaking from. Might save you some work.
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Old 02-21-2018, 12:36 PM
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Old 02-21-2018, 03:22 PM
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Originally Posted by stingr69 View Post
Oil leaking from anywhere will make you think it is the rear main seal or oil pan. Degrease the engine well and hit it with talcum powder then drive for a few miles to see exactly where the oil is actually leaking from. Might save you some work.

excellent advice
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Old 02-21-2018, 08:17 PM
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That is all good advice. Now that my stater is back up and working I'll back it out and give it a good hose down. Thanks much.
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Old 02-23-2018, 07:41 AM
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Wasn't that bad...

Last edited by derekderek; 02-23-2018 at 09:29 AM.
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Old 02-23-2018, 09:29 AM
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...

Last edited by derekderek; 02-23-2018 at 10:07 AM.
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