Author Topic: Leaking rear differential seal  (Read 1586 times)

Offline Chlngrcrzy

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Leaking rear differential seal
« on: November 19, 2016 - 11:29:23 AM »
How hard is it to change the seal in an 8 3/4 rear end? Do i need to pull the complete punkin out?  Seals are available where?




Offline GoodysGotaCuda

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Re: Leaking rear differential seal
« Reply #1 on: November 19, 2016 - 01:59:40 PM »
The pinion seal or the 3rd member to housing seal?
Build Page: Goody's 'Cuda Build Page
1976 Dodge Warlock
1972 Barracuda - 5.7 Hemi + T56 Magnum

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Offline dakota

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Re: Leaking rear differential seal
« Reply #2 on: November 19, 2016 - 02:27:12 PM »
The yoke can be removed with a steering wheel puller mounted on the u-joint saddles.  It's my understanding that you could replace the seal without a full tear down, but the trick will be to avoid over-torquing the nut on the differential yoke when you put everything back together (this assumes you have a stock arrangement with a crush sleeve on the pinion vs. a solid sleeve like what's sold by Dr Diff).  The diff yoke nut sets the preload on the pinion bearings.  The preload is measured in inch-pounds, usually with a beam torque wrench. Rotating the nut 1/8th of a turn can cross you over from "ok" to "too much".  I don't have my service manual with me right now, but the preload target was small - something like 10 inch pounds or less.  If you overshoot on the preload, it's a one way trip with the crush sleeve (ask me how I know).  With the Dr Diff "crush sleeve eliminator" in place, you can just back off the yoke nut until you get the right preload.

In the YouTube videos I've watched, there was a good recommendation for reassembly:  put sealant on the yoke splines as well as the outside edge of the seal to prevent leaks.

Good luck on whatever you decide to do. 

Offline Chlngrcrzy

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Re: Leaking rear differential seal
« Reply #3 on: November 19, 2016 - 04:01:22 PM »
The pinion seal or the 3rd member to housing seal?
pinion

Offline jimynick

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Re: Leaking rear differential seal
« Reply #4 on: November 19, 2016 - 08:15:36 PM »
I changed mine and took a centre punch and marked the pinion nut and shaft at the same spot. Then I counted the turns the pinion nut took to come off and pulled the seal. I used sealant on the seal and pumpkin putting it back together and using an impact gun, ran the nut up to the marks. I've got several hundred miles on it so far and (touching wood) so good.  :cheers:

Offline GoodysGotaCuda

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Re: Leaking rear differential seal
« Reply #5 on: November 19, 2016 - 08:16:36 PM »
I changed mine and took a centre punch and marked the pinion nut and shaft at the same spot. Then I counted the turns the pinion nut took to come off and pulled the seal. I used sealant on the seal and pumpkin putting it back together and using an impact gun, ran the nut up to the marks. I've got several hundred miles on it so far and (touching wood) so good.  :cheers:

Yep, that's what he is going to need to do. Don't forget the RTV around the seal where it goes into the 3rd member, as mentioned.
Build Page: Goody's 'Cuda Build Page
1976 Dodge Warlock
1972 Barracuda - 5.7 Hemi + T56 Magnum

Wheel & Tire Specs:Link

Offline Chlngrcrzy

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Re: Leaking rear differential seal
« Reply #6 on: November 19, 2016 - 09:23:09 PM »
Thanks for all the helpful information. The seal should be readily available at most auto parts stores?

Offline GoodysGotaCuda

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Re: Leaking rear differential seal
« Reply #7 on: November 19, 2016 - 09:31:21 PM »
Thanks for all the helpful information. The seal should be readily available at most auto parts stores?

I would get online and see what number you need exactly, they may be different between case types?
Build Page: Goody's 'Cuda Build Page
1976 Dodge Warlock
1972 Barracuda - 5.7 Hemi + T56 Magnum

Wheel & Tire Specs:Link