th400 trans problems........need help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*project 67 sub* · 08-14-2008, 05:17 PM

ok. so i replaced the selector shaft seal, and it still leaks like a siv. so can i pack some silicon or something around the selector shaft so i dont have to pull my trans. all back apart to try and fix it again and possibly still have the same problem. any help is greatly appreciated.

Bus Ted Knuckle · 08-14-2008, 05:21 PM

Packing RTV around it will only make your fingers messy. If it was the correct seal, then there must be a groove around the shaft. I'd pull it back out to see what the deal is, you want to fix it right don't ya? nows the time!

kelsfine69 · 08-14-2008, 09:36 PM

You might have nicked the seal putting it in. Check for a groove where the seal rides. A new seal should fix her up.. I cant remeber if you can pull the shaft with just dropping the pan.

jeffspower · 08-15-2008, 12:47 AM

I use a special tool that draws the old seal out without removing the shaft. You will probably find a gouge in the case bore from prying it out, a nick or wear in the shaft, or if you didn't de- bugger the end of the shaft when sliding it thru the seal, it might have damaged the seal lip. You also want to rotate it as you start it into the seal, so it doesn't try to roll the lip.

08-14-2008, 05:17 PM	#1
project 67 sub Account Suspended Join Date: Mar 2007 Location: san bernardino ca. everywhere Posts: 3,938	th400 trans problems........need help ok. so i replaced the selector shaft seal, and it still leaks like a siv. so can i pack some silicon or something around the selector shaft so i dont have to pull my trans. all back apart to try and fix it again and possibly still have the same problem. any help is greatly appreciated.

08-14-2008, 05:21 PM	#2
Bus Ted Knuckle Son of a gun Join Date: Jan 2007 Location: Hot Springs, Arkansas Posts: 1,636	Re: th400 trans problems........need help Packing RTV around it will only make your fingers messy. If it was the correct seal, then there must be a groove around the shaft. I'd pull it back out to see what the deal is, you want to fix it right don't ya? nows the time! __________________ Bill BEATERS ARE NEATER Last edited by Bus Ted Knuckle; 08-14-2008 at 05:24 PM.

08-14-2008, 09:36 PM	#3
kelsfine69 18 Till I Die Join Date: Mar 2005 Location: Alberta, Canada Posts: 1,522	Re: th400 trans problems........need help You might have nicked the seal putting it in. Check for a groove where the seal rides. A new seal should fix her up.. I cant remeber if you can pull the shaft with just dropping the pan. __________________ 2011 GMC Acadia 1969 GMC BBC LS7 2007 GMC Crew Duramax 1987 Camaro Iroc 350 Tuned Port Injection 42000Km 1987 Chevrolet Silverado 350 TBI 1987 Chevrolet Silverado 350 TBI(yes 2) Take me drunk, I'm too home...

08-15-2008, 12:47 AM	#4
jeffspower Well, Whoop-dee-do! Join Date: Mar 2003 Location: Easton, Mo. pop.- me & scarcely a few others Posts: 2,302	Re: th400 trans problems........need help I use a special tool that draws the old seal out without removing the shaft. You will probably find a gouge in the case bore from prying it out, a nick or wear in the shaft, or if you didn't de- bugger the end of the shaft when sliding it thru the seal, it might have damaged the seal lip. You also want to rotate it as you start it into the seal, so it doesn't try to roll the lip. __________________ '68 GMC shortbox 4x4 350/SM465/T221- bought it in '83 SOLD '72 K20 500 Cad/TH400/NP205 SOLD '92 Chevy 2500 6.5 mech TD 4L80E crusty daily driver '72 Monte Carlo... sweet low mile toy '11 Dodge Challenger IE 392 6spd... midlife car



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