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Diff leaking
Posted by: Benfro ()
Date: July 31, 2020 09:09PM

Hey there. Hoping get some advise from experienced Corvair guys or gals. The differential in my 62 Spyder seems to be puking oil from the top somewhere. Thought it was coming from the top diff cover. Sealed it up and it still leaks. Then I thought it was overfilled. Checked levels and they were even with the fill holes. Drove it about an hour and half up these Montana mountain roads and when I would go uphill the transaxle oil would spill on the exhaust crossover pipe and smoke something awful. Got it home and checked again. The levels were about .5" to .75" below fill line. So question, if the diff cover is sealed and the vent hole has scotch Brite type material in the tube, where could it be leaking from up there? The tranny to diff bolts are tight. Its a 62 posi diff, rebuilt by Paul Kehler. The car drives great aside from this gear oil issue. It currently has Amsoil 75-90 in it. Thanks in advance. I'm probably going to pull the drivetrain to inspect but thought I would check here first.

Ben

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Re: Diff leaking
Posted by: jamesolefjensen ()
Date: July 31, 2020 09:55PM

Try snapping a picture of the top cover vent and look for evidence of puking. Maybe something is wrong with the it. On my later Saginaw transaxle, the vent fitting/cap is captivated but loose. My guess is gravity keeps it closed but under a little bit of pressure it can burp. Perhaps in your case it's stuck open or something.

There's also a baffle on the inside of the cover. In your case is it still intact?

James
65 Corsa
SF Bay Area

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Re: Diff leaking
Posted by: JimBrandberg ()
Date: August 01, 2020 06:30AM

Are you sure it isn't axle yokes loose in their bores? I have to do something one day soon as I have several EM differentials with this problem. The side seal just can't cope.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Diff leaking
Posted by: Wagon Master ()
Date: August 01, 2020 06:54AM

jamesolefjensen Wrote:
-------------------------------------------------------
There's also a baffle on the inside of the cover. In your case is it still intact?


If it has the original diff. cover, I'm not sure a 62 Spyder would have the later revision cover baffle/deflector.

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Re: Diff leaking
Posted by: Benfro ()
Date: August 01, 2020 08:28AM

I thought it maybe the axle seals but they seem tight. I'll look again. If I reach up and feel the top of the diff cover it is pooled with fluid. When I had it off to reseal it wasn't cracked or damaged. My Diff cover doesn't have a baffle built in. If it was an axle seal there's no way it could pool up top, right?

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Re: Diff leaking
Posted by: TerribleTed ()
Date: August 01, 2020 08:47AM

You would not get get puddles on top from axle seal leaks.

---------------------------------------------------------------------------------------------------------

Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.
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Re: Diff leaking
Posted by: RexJohnson ()
Date: August 01, 2020 08:54AM

GM changed the location of the vent somewhere around '64? The vent was first towards the rear of the car and then it was moved to the front. Later the baffle was added and it helps shield the vent from being hit by oil. If it is coming out of the vent and the vent is towards the rear maybe a later cover would help? Maybe if you could clean up the oil and then drive it a short distance and take a picture to see where the oil is coming from that way you know what to fix.

RJ tools
Salem,Oregon

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Re: Diff leaking
Posted by: steve c goodman ()
Date: August 01, 2020 09:22AM

Benfro in your first post you mention scotch brite material at vent. Is is inside the vent or wrapped around it or?

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry

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Re: Diff leaking
Posted by: Benfro ()
Date: August 01, 2020 09:43AM

Steve, from the looks of it, Paul put the green material inside the vent tube when he rebuilt it. Not the typical maroon type Scotch Brite stuff. I left it in there, figured it would help with seepage.

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Re: Diff leaking
Posted by: TIBCO ()
Date: August 01, 2020 12:03PM

I believe the aforementioned baffle came out in 67 or later. My early (Nov) build 66 doesn't have it. Could someone post a picture of a top cover with the baffle?

I believe there was an article in the Tech Guide about it.

Cliff Tibbitts
Nicholasville, KY
CORSA, CKCE, Derby City Corvairs
66 Monza, 140/4sp

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Re: Diff leaking
Posted by: joelsplace ()
Date: August 01, 2020 01:54PM

You know since GM moved the vent and added a baffle they must have been having trouble. A late cover will probably fix it.
I have a '61 that pukes. No other Corvair I've had does. Baffling.

Joel
Northlake, TX
5 Ultravans, 114 Corvairs and counting...

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Re: Diff leaking
Posted by: steve c goodman ()
Date: August 01, 2020 02:11PM

The only diff I have had with vent issues was a 64pg convert several years ago. Vent on diff top was plugged and pressure would push diff grease out of axle check dipstick. In fact the pressure was so high it would push dipstick half way out of the tube. It didn't take many miles to do it either and at slow speeds.

I just replaced diff cover and it was cured. The cover and around the vent had a clay like substance that covered/coated the entire cover.

This is why I asked about the scotch brite material stuck in vent in my post above above.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry



Edited 1 time(s). Last edit at 08/01/2020 02:14PM by steve c goodman.

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Re: Diff leaking
Posted by: JimBrandberg ()
Date: August 02, 2020 09:11AM

Yes not the axle seals. You have to get cozy to remove the top cover in the chassis. Bet you can't do it without getting grease on your face.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Diff leaking
Posted by: steve c goodman ()
Date: August 02, 2020 09:27AM

I was lucky Jim, I removed the starter (and tire/wheel of course) and cleaned around the edge of the diff cover so nothing could fall into diff and removed the 6 bolts and it lifted off with minimal prying. Gasket surface was clean on diff top so replacing was easy too.

Funny thing too, it never showed leakage around the diff side seals, just pushed the axle check dipstick part way out of tube and wet engine corner with gear lube.

I darn sure didn't want to charge for powertrain R&R just to service diff cover.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry

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