NP 205 help- leaving puddles, big puddles - The 1947 - Present Chevrolet & GMC Truck Message Board Network

71 super · 01-01-2009, 03:05 PM

Friend recently purchased a 71 1/2 ton 4x4 swb auto. Previous owner stated trans was leaking and that was why he stopped driving it. After getting it home and replacing output shaft seals and output housing gaskets and cracked speedo cable, leaking stopped for 2 days, now it is leaking again. This time from the lower shift rail for high low range. I know there is a seal in there I can see it, question is how do I go about replacing it? I have looked at several t/c break downs and it looks like it all has to come apart. Is there another way? Thanks for your help. Harold

hdflstf · 01-01-2009, 05:32 PM

Sounds like you may still be having trans fluid leaking into the TC? My guess is the two seals inside the TC to trans adapter are installed in the wrong direction. The fluid leaking out the lower shift shaft says the fluid level in the TC is way too high. You can replace the seal there without dis-assembling the entire TC but it will be a pain.

71 super · 01-01-2009, 06:05 PM

Thank you!

hdflstf · 01-01-2009, 06:50 PM

Check this thread http://67-72chevytrucks.com/vboard/s...d.php?t=266278
There's a couple of pictures that show the adapter seals so you can see the installation direction (they are reversed from what you would normally expect).

LONGHAIR · 01-01-2009, 07:14 PM

As a general rule rubber "lip" seals are installed with the side that has the spring going toward the liquid side. It doesn't matter whether the liquid is ATF, gear oil, motor oil, grease, etc.
Occasionally you will come across one with two lips, but only one will have the spring.

01-01-2009, 03:05 PM	#1
71 super Registered User Join Date: Sep 2005 Location: Canton North carolina Posts: 3,080	NP 205 help- leaving puddles, big puddles Friend recently purchased a 71 1/2 ton 4x4 swb auto. Previous owner stated trans was leaking and that was why he stopped driving it. After getting it home and replacing output shaft seals and output housing gaskets and cracked speedo cable, leaking stopped for 2 days, now it is leaking again. This time from the lower shift rail for high low range. I know there is a seal in there I can see it, question is how do I go about replacing it? I have looked at several t/c break downs and it looks like it all has to come apart. Is there another way? Thanks for your help. Harold __________________ 67 blue step side- bb 68 gold and white swb cst anniversary 68 custom swb hot rod Ls swap 69 swb cst 6 cylinder/ overdrive 69 black/black cst bb swb 70 orange and white cst Canada built truck swb bb 71 black and white super swb bb 71 red and white super swb 72 green and white super swb 4x4 62 nova wagon 400 series Ls swapped 68 Camaro 327/4 speed- 1 owner, original paint 66 Volkswagen bettle 69 auto stick Volkswagen Beetle

01-01-2009, 05:32 PM	#2
hdflstf Registered User Join Date: Oct 2007 Location: Desert Southwest Posts: 540	Re: NP 205 help- leaving puddles, big puddles Sounds like you may still be having trans fluid leaking into the TC? My guess is the two seals inside the TC to trans adapter are installed in the wrong direction. The fluid leaking out the lower shift shaft says the fluid level in the TC is way too high. You can replace the seal there without dis-assembling the entire TC but it will be a pain.

01-01-2009, 06:05 PM	#3
71 super Registered User Join Date: Sep 2005 Location: Canton North carolina Posts: 3,080	Re: NP 205 help- leaving puddles, big puddles Thank you! __________________ 67 blue step side- bb 68 gold and white swb cst anniversary 68 custom swb hot rod Ls swap 69 swb cst 6 cylinder/ overdrive 69 black/black cst bb swb 70 orange and white cst Canada built truck swb bb 71 black and white super swb bb 71 red and white super swb 72 green and white super swb 4x4 62 nova wagon 400 series Ls swapped 68 Camaro 327/4 speed- 1 owner, original paint 66 Volkswagen bettle 69 auto stick Volkswagen Beetle

01-01-2009, 06:50 PM	#4
hdflstf Registered User Join Date: Oct 2007 Location: Desert Southwest Posts: 540	Re: NP 205 help- leaving puddles, big puddles Check this thread http://67-72chevytrucks.com/vboard/s...d.php?t=266278 There's a couple of pictures that show the adapter seals so you can see the installation direction (they are reversed from what you would normally expect).

01-01-2009, 07:14 PM	#5
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: NP 205 help- leaving puddles, big puddles As a general rule rubber "lip" seals are installed with the side that has the spring going toward the liquid side. It doesn't matter whether the liquid is ATF, gear oil, motor oil, grease, etc. Occasionally you will come across one with two lips, but only one will have the spring.



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