Gear Select Shaft Seal Replacement - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TjBlueRusty · 03-22-2010, 06:07 PM

The gear select shaft seal on a TH350 transmission is leaking. I found a tool that removes it from the outside but it will not thread into the seal.
My next option is to drop the pan and remove the shaft. Can someone tell me if the gear select shaft can be removed after dropping the pan or is it more complicated? Thanks for the help.

LONGHAIR · 03-22-2010, 07:39 PM

Yes it can, but it's a bit more complicated. IIRC, the valve body has to be removed?
I'm pretty sure that is the point of the removal tool, so you can remove the seal from the outside.

TjBlueRusty · 03-24-2010, 07:39 PM

Thanks Longhair. I went ahead and dropped the pan to have a look. After removing a S clip and a roller arm the linkage moved enough to remove the retaining nut. Had to deburr the shaft (Dremel) then it came right out and then was able to pry out the seal.
I had a lot of fear about parts dropping off after opening up the transmission but it was fairly simple.
I do have another dilemma. The new seal appears to fit around the shaft but it easily slides up and down on the shaft. I figured a new seal would fit tight and have some resistance when sliding it on the shaft. Is this normal or do I need to get another seal (GM). This one came from O'Reilly's and matched the old one. NAPA's seal only was about half the originals height.
Thanks again for the help.

TjBlueRusty · 03-25-2010, 02:59 PM

Anyone have any seal recommendations or experiences as to what to get or not to get? Ones that failed and ones that worked?

I do not want to do this again and I've looked at 2 seals that are different.

Thanks.

03-22-2010, 06:07 PM	#1
TjBlueRusty Registered User Join Date: Jun 2009 Location: Shawnee, KS Posts: 10	Gear Select Shaft Seal Replacement The gear select shaft seal on a TH350 transmission is leaking. I found a tool that removes it from the outside but it will not thread into the seal. My next option is to drop the pan and remove the shaft. Can someone tell me if the gear select shaft can be removed after dropping the pan or is it more complicated? Thanks for the help.

03-24-2010, 07:39 PM	#3
TjBlueRusty Registered User Join Date: Jun 2009 Location: Shawnee, KS Posts: 10	Re: Gear Select Shaft Seal Replacement Thanks Longhair. I went ahead and dropped the pan to have a look. After removing a S clip and a roller arm the linkage moved enough to remove the retaining nut. Had to deburr the shaft (Dremel) then it came right out and then was able to pry out the seal. I had a lot of fear about parts dropping off after opening up the transmission but it was fairly simple. I do have another dilemma. The new seal appears to fit around the shaft but it easily slides up and down on the shaft. I figured a new seal would fit tight and have some resistance when sliding it on the shaft. Is this normal or do I need to get another seal (GM). This one came from O'Reilly's and matched the old one. NAPA's seal only was about half the originals height. Thanks again for the help.

03-25-2010, 02:59 PM	#4
TjBlueRusty Registered User Join Date: Jun 2009 Location: Shawnee, KS Posts: 10	Re: Gear Select Shaft Seal Replacement Anyone have any seal recommendations or experiences as to what to get or not to get? Ones that failed and ones that worked? I do not want to do this again and I've looked at 2 seals that are different. Thanks.



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