Some Pinion Seal Help Please - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Zonaman · 11-24-2008, 12:14 PM

Looks like my differential is leaking where the driveshaft connects. That's a pinion seal , I presume? I read up on it in my Haynes manual and it looks like something I can do but I have a few questions:

The procedure is slightly different if you have a semi-floating rear axel. How can you tell?
There's a small piece of duct tape between the u-bolt and the u-joint. What's up with that? Not some "cheapout instead of fix it right trick", I hope.

If it makes any difference,- it's a posi-traction diff, a 2-piece drivershaft, and it's been converted to a 700R4 trannie. See photos below and thnaks in advance!

larry may · 11-24-2008, 12:28 PM

Remove the drive shaft from the differential yoke. Throw the duct tape away. Center punch the pinion nut and shaft. Remove the nut pull the ypke. Pry out the leaking seal . Install the new seal , then the yoke now the washer and nut . May not have a washer. Tighten the nut back to the center punched dot. Then tighten an 1/8th inche past the punched dot. Reinstall the drive shaft go for a ride. Location of the duct tape would not do much as a shim there. Could be was around the ujoints to keep the caps from falling off the ujoint journals . Have fun. Takes about and hour to do this and one cool one.

Zonaman · 11-28-2008, 09:11 PM

Thanks, Larry. So far so good, I managed to disassmeble the thing and get a seal in before dark. Question: I noted that the old seal wasn't tapped in all the way. There was about an 1/8 inch gap all around the outer colar. The manual says to tap it in "to its full depth." Any reason why I shouldn't have it all the way down?

Thanks.

larry may · 11-28-2008, 09:48 PM

Could be the wrong replacement . Try to look in past the seal and see if it is bottomed out. If not then find or make a driver to fit the outer of the seal and drive it on in. If you be careful and gentle, can tap around the outer edge and get it to go. If you get real rough with it the spring ring can come out of the seal then it was all to do over . Not a real big deal to change just tap it in . Should be fine.

msgross · 11-28-2008, 09:57 PM

I think I also put some flexible sealant around the grooves of the pinion before I put the yoke back on...

one of my manuals had that info

Alex Hayley · 11-28-2008, 11:46 PM

I did exactly this job not too long ago. First, the seal will not seat all the way to the housing. A gap is expected. As you tap the seal in the sound of the tapping will change when the seal is seated. Second, it is very important to put some sealant between the seal and housing otherwise it will leak(ask me how I know). Third, mark the position of the nut to the pinion shaft AND count the number of turns to remove the nut. Ensure you exactly reverse the number of turns when reinstalling.

JimKshortstep4x4 · 11-29-2008, 06:12 AM

Make sure the axle vent is not plugged. A plugged axle vent will cause a pressure build up in the differential forcing the fluid out.

Jim

LONGHAIR · 11-29-2008, 11:02 AM

Quote:

Originally Posted by Alex Hayley

mark the position of the nut to the pinion shaft AND count the number of turns to remove the nut. Ensure you exactly reverse the number of turns when reinstalling.

That is not necessary at all. This is a normal single start thread, it will always turn the same amount of revolutions to get back the the same place. The idea is to get it tight again w/o overtightening to the point of crushing the "crush-sleeve" any more. A little Lock-Tite goes a long way in a project like this. Originally it probably took over 200 ft-lbs of torque to get it crushed properly, but now somewhere around 100 ft-lbs and some Lock-Tite Red will be fine.

Zonaman · 11-29-2008, 11:34 AM

Quote:

Originally Posted by msgross

I think I also put some flexible sealant around the grooves of the pinion before I put the yoke back on...

one of my manuals had that info

Thanks again for all the help. What type of sealant should I use on the splines?

msgross · 11-29-2008, 12:56 PM

I just went to autozone near the RTV section and found a small tube of "flexible" sealant...

RTV might even work...

Zonaman · 11-29-2008, 04:36 PM

Put it all together (made sure vent was clear) and took a test drive. All better now. I love this Forum!

Guess I better check the gear oil level. The square bolt on the side in the middle photo above- Is that the filler hole? What would I use in there with posi-traction?

larry may · 11-29-2008, 08:23 PM

I use 80'90 then add the small botle of posi lube. Any parts store carries the posi lube.

11-24-2008, 12:14 PM	#1
Zonaman Registered User Join Date: May 2004 Location: Chandler, AZ Posts: 519	Some Pinion Seal Help Please Looks like my differential is leaking where the driveshaft connects. That's a pinion seal , I presume? I read up on it in my Haynes manual and it looks like something I can do but I have a few questions: The procedure is slightly different if you have a semi-floating rear axel. How can you tell? There's a small piece of duct tape between the u-bolt and the u-joint. What's up with that? Not some "cheapout instead of fix it right trick", I hope. If it makes any difference,- it's a posi-traction diff, a 2-piece drivershaft, and it's been converted to a 700R4 trannie. See photos below and thnaks in advance! Attached Images __________________ 69 C-10 LWB, 350, 700r4, 3.73 posi-traction, front disc brakes. Built for the desert- She can take the heat! Vivat Rex Chevus! Last edited by Zonaman; 11-24-2008 at 02:03 PM.

11-24-2008, 12:28 PM	#2
larry may Senior Member Join Date: Jul 2005 Location: MISSOURI Posts: 3,256	Re: Some Pinion Seal Help Please Remove the drive shaft from the differential yoke. Throw the duct tape away. Center punch the pinion nut and shaft. Remove the nut pull the ypke. Pry out the leaking seal . Install the new seal , then the yoke now the washer and nut . May not have a washer. Tighten the nut back to the center punched dot. Then tighten an 1/8th inche past the punched dot. Reinstall the drive shaft go for a ride. Location of the duct tape would not do much as a shim there. Could be was around the ujoints to keep the caps from falling off the ujoint journals . Have fun. Takes about and hour to do this and one cool one. __________________ The biggest problem people have, is other people Thou shalt be cool and not hassle Be a site supporter. The heart of the wise inclines to the right, but the heart of the fool inclines to the left." Ecclesiastes 10:2

11-28-2008, 09:11 PM	#3
Zonaman Registered User Join Date: May 2004 Location: Chandler, AZ Posts: 519	Re: Some Pinion Seal Help Please Thanks, Larry. So far so good, I managed to disassmeble the thing and get a seal in before dark. Question: I noted that the old seal wasn't tapped in all the way. There was about an 1/8 inch gap all around the outer colar. The manual says to tap it in "to its full depth." Any reason why I shouldn't have it all the way down? Thanks. __________________ 69 C-10 LWB, 350, 700r4, 3.73 posi-traction, front disc brakes. Built for the desert- She can take the heat! Vivat Rex Chevus! Last edited by Zonaman; 11-28-2008 at 09:22 PM.

11-28-2008, 09:48 PM	#4
larry may Senior Member Join Date: Jul 2005 Location: MISSOURI Posts: 3,256	Re: Some Pinion Seal Help Please Could be the wrong replacement . Try to look in past the seal and see if it is bottomed out. If not then find or make a driver to fit the outer of the seal and drive it on in. If you be careful and gentle, can tap around the outer edge and get it to go. If you get real rough with it the spring ring can come out of the seal then it was all to do over . Not a real big deal to change just tap it in . Should be fine. __________________ The biggest problem people have, is other people Thou shalt be cool and not hassle Be a site supporter. The heart of the wise inclines to the right, but the heart of the fool inclines to the left." Ecclesiastes 10:2

11-28-2008, 09:57 PM	#5
msgross Registered User Join Date: Jul 2006 Location: Central PA Posts: 12,201	Re: Some Pinion Seal Help Please I think I also put some flexible sealant around the grooves of the pinion before I put the yoke back on... one of my manuals had that info __________________ The Garage: 1968 K-10 SWB - "Project Money Pit" 1996 Z-71 - "huntin rig" 1969 C-10 LWB (SOLD) "Project flip that truck or else" 1993 Passport, F@rd 1-ton (SOLD)"Project Cousin Eddie" My Garage Build "The 1,000 footer" Last edited by msgross; 11-28-2008 at 09:57 PM.

11-28-2008, 11:46 PM	#6
Alex Hayley Registered User Join Date: Jul 2000 Location: NC Posts: 987	Re: Some Pinion Seal Help Please I did exactly this job not too long ago. First, the seal will not seat all the way to the housing. A gap is expected. As you tap the seal in the sound of the tapping will change when the seal is seated. Second, it is very important to put some sealant between the seal and housing otherwise it will leak(ask me how I know). Third, mark the position of the nut to the pinion shaft AND count the number of turns to remove the nut. Ensure you exactly reverse the number of turns when reinstalling.

11-29-2008, 06:12 AM	#7
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Some Pinion Seal Help Please Make sure the axle vent is not plugged. A plugged axle vent will cause a pressure build up in the differential forcing the fluid out. Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

11-29-2008, 12:56 PM	#10
msgross Registered User Join Date: Jul 2006 Location: Central PA Posts: 12,201	Re: Some Pinion Seal Help Please I just went to autozone near the RTV section and found a small tube of "flexible" sealant... RTV might even work... __________________ The Garage: 1968 K-10 SWB - "Project Money Pit" 1996 Z-71 - "huntin rig" 1969 C-10 LWB (SOLD) "Project flip that truck or else" 1993 Passport, F@rd 1-ton (SOLD)"Project Cousin Eddie" My Garage Build "The 1,000 footer"

11-29-2008, 04:36 PM	#11
Zonaman Registered User Join Date: May 2004 Location: Chandler, AZ Posts: 519	Re: Some Pinion Seal Help Please Put it all together (made sure vent was clear) and took a test drive. All better now. I love this Forum! Guess I better check the gear oil level. The square bolt on the side in the middle photo above- Is that the filler hole? What would I use in there with posi-traction? __________________ 69 C-10 LWB, 350, 700r4, 3.73 posi-traction, front disc brakes. Built for the desert- She can take the heat! Vivat Rex Chevus! Last edited by Zonaman; 11-29-2008 at 05:06 PM.

11-29-2008, 08:23 PM	#12
larry may Senior Member Join Date: Jul 2005 Location: MISSOURI Posts: 3,256	Re: Some Pinion Seal Help Please I use 80'90 then add the small botle of posi lube. Any parts store carries the posi lube. __________________ The biggest problem people have, is other people Thou shalt be cool and not hassle Be a site supporter. The heart of the wise inclines to the right, but the heart of the fool inclines to the left." Ecclesiastes 10:2



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