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shift shaft seal
Posted by: threno ()
Date: August 22, 2019 11:14AM

First, I read every thread I could find and am still baffled. I just replaced the shift shaft seal on my 66 Corsa. In two days, there was a puddle of gear oil the size of a dinner plate under the car. Here are the details:

1. It was installed with the largest size socket possible.
2. I did NOT use gasket sealer between the metal parts.
3. The inner parts of the rubber were sealed with "petrolatum" as per the
factory manual.
4. The new seal came from Clarks.
5. The rest of the trans was cleaned with mineral spirits to check if leak was
from somewhere else.
6. I didn't polish the shaft and the seat. Didn't know how to get in there.
7. There didn't appear to be any damage or rust on shaft or seat.

The new seal was pulled. A close look inside looks as though there is an "O" ring seal further in. Am I seeing things? Shadows? A look at the 65 manual's factory diagram doesn't indicate a second seal. Was there an "O" ring on '66 models? Do I need to replace an "O" ring too?

Finally, did I somehow screw up the first time? Thanks for the help.

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Re: shift shaft seal
Posted by: larry202br ()
Date: August 22, 2019 11:33AM

Did you get C497, the improved seal? it is like two seals in one.

1961 rampside with a 65 / 67 110 engine, car four speed.
1965 convertible
1966 Custom two door/four door 180 Turbo.

Olathe, ks

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Re: shift shaft seal
Posted by: vairchet ()
Date: August 22, 2019 11:37AM

Pin holes on shifter shaft more than likely cut lip of seal. Protective sleeve is necessary when installing a new seal. Rust and debris will also contribute to seal failure.

No, there isn't an additional O-ring or seal beyond what is factory, unless previous owner added a jury-rig.

Chet in Ramona

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Re: shift shaft seal
Posted by: threno ()
Date: August 22, 2019 05:15PM

Yes, I did get the new seal from Clarks
What do you recommend using as a sleeve?
Thanks all

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Re: shift shaft seal
Posted by: solo2r ()
Date: August 22, 2019 10:34PM

Make sure the coupler pin hole on shaft does not have sharp edges around the hole. That will take out a seal even before you get to use the socket to hammer it in!

Take a flat file to that hole.

Edited 1 time(s). Last edit at 08/22/2019 10:35PM by solo2r.

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Re: shift shaft seal
Posted by: davemotohead ()
Date: August 22, 2019 10:36PM

You can wrap tape around the shaft to cover the hole so the sharp edges don't cut the seal then slide the seal over it.

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)

Rust Free Lancaster Ca

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Re: shift shaft seal
Posted by: JimBrandberg ()
Date: August 23, 2019 05:08AM

Dinner plate size is a lot over a few days. Good suggestions above to check. The metal to metal outside surface of the seal is usually okay.

It's been reported by some people find that they drip when sitting in first gear but not so much in second gear, or vice versa.

Jim Brandberg
Isanti, MN

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Re: shift shaft seal
Posted by: irfgt ()
Date: August 23, 2019 10:32AM

Not adding some RTV sealer around the outside of the seal to the transmission case is probably your problem. The two metal surfaces are very leak prone especially on automatic transmission converter seals.

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Re: shift shaft seal
Posted by: joelsplace ()
Date: August 23, 2019 06:44PM

You can also wrap a thin plastic bag around the shaft to slide the seal on.

Northlake, TX
5 Ultravans, 113 Corvairs and counting...

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Re: shift shaft seal
Posted by: caroseiii ()
Date: August 23, 2019 07:02PM

Indian shellac on the perimeter of the seal is your friend.


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Re: shift shaft seal
Posted by: threno ()
Date: September 07, 2019 07:28AM

First, let me say, "Thank you, thank you, thank you!!!" to all of you for your suggestions.

Now the bad news. After putting in two more seals, it still leaks. The second seal leaked because it was installed from under the car and I put it in crooked. The dinner plate-sized puddle from the first seal was gone, but still leaking. The thrid seal went in correctly, but still had a slight leak.

Not being one to settle for a slight leak, I pulled the drivetrain (Only took about a half hour. The drivetrain was just going back in when the new leak was initially discovered) This allowed a close look. The problem is a gouge in the side of the transmission case. It looks like someone drove a screwdriver between the case and seal to remove one. I plead, "Not guilty."

What's the best way to fix the gouge? I've been putting sealant on the seal. I suspect most is being scraped off as the seal goes in and there isn't enough to completely fill the gouge. Should the sealant be put in the qouge and risk having the seal push it into the shaft and case? Should the gouge be filled with JB weld and hopefully smoothed to the correct contour? If you have found a fix for this I'd be grateful to hear it.

Finally, here are some tips I would offer:
1 Inspect everything carefully. A small dental mirror might help when
under the car.
2 Remove the back of the tunnel cover and the two bolts connected to the
transmission mount. This will allow the shifter assembly to be swung down
and over so you can get the seal inserted squarely.
3 Punch a hole in the old seal, insert a self-tapping screw, and use that to
pull the old seal. Don't pry it out with a screwdriver!

Thanks again to all. I'll keep you posted.

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Re: shift shaft seal
Posted by: irfgt ()
Date: September 07, 2019 09:14AM

If you didn't use grey colored RTV sealer you wasted your time.

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Re: shift shaft seal
Posted by: Frank DuVal ()
Date: September 07, 2019 09:22AM

If you could get JB Weld in the gouge and sand the hole round, it should work fine.

Clean clean clean the cast iron before applying the JB Weld. Not sure how one would do this with the drivetrain level and gear oil in the transmission.... Maybe jack up the "front" of the assembly enough tho get the gear oil to not be at the shifter rod.

Frank DuVal

Fredericksburg, VA

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