Topic: Differential Seals
in Forum: C3 Driveline Components
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Former Member
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, - USA
Joined: 11/8/2003
Posts: 21
Vette(s): 1971 Convertible, black on black with white top.
454, Hurst 4-speed. No Power Brakes, Steering or Windows.
I am redoing my 71 big block convertible 4 speed. I am starting at the rear end. I need some information.
My seals in the diff are all leaking and it needs some TLC.
Could I just install new seals, and can this be done on the outside or would I have to pull the differential? And one more thing. This was originally a big block car and I have the motor at a good race shop to be redone. I will be in the area of 576 hp with 591 lbs of torque. Should I have the rear diff upgraded with stronger stuff to accept the new power, or would the stock diff be ok?
Thanks in advance for any help,
Ron
My seals in the diff are all leaking and it needs some TLC.
Could I just install new seals, and can this be done on the outside or would I have to pull the differential? And one more thing. This was originally a big block car and I have the motor at a good race shop to be redone. I will be in the area of 576 hp with 591 lbs of torque. Should I have the rear diff upgraded with stronger stuff to accept the new power, or would the stock diff be ok?
Thanks in advance for any help,
Ron

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Former Member
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Portland, TN - USA
Joined: 4/29/2003
Posts: 805
Vette(s): 1972 Coupe
Anything, but Stock and more mods to come!
SSBC Force 10 Brakes, 3.73, TH350, 355 CID, Rack and Pinion, Vette Brakes suspension front and rear.
It will be next to impossible to replace the front seal. Even if you can get it apart while still in the chassis if you remove the front input yoke you have just removed any pinion clearance that was set with the crush sleeve when it was assembled so it will need to be reset. My suggestion would be to pull the diff and redo it.
What you also need to remember is if a seal allows for oil to leak out then its highly likely something can find its way inside just as easily.
What you also need to remember is if a seal allows for oil to leak out then its highly likely something can find its way inside just as easily.

Agreeded. With the diff out you can remove the pinion nut and yoke and change the seal. If you marked the nut and return it to it's original position, then tighten and additional 1/8 turn it would be okay.
BUT.... with that kind of horsepower I would go through the entire diff and install new bearings etc. Also check at Summit or Jegs or another high performance supplier. There is a rear cover available that will reinforce and add strength to the housing. Again, with that much power it would be a good idea.
Ken Styer
BUT.... with that kind of horsepower I would go through the entire diff and install new bearings etc. Also check at Summit or Jegs or another high performance supplier. There is a rear cover available that will reinforce and add strength to the housing. Again, with that much power it would be a good idea.
Ken Styer
Former Member
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, - USA
Joined: 11/8/2003
Posts: 21
Vette(s): 1971 Convertible, black on black with white top.
454, Hurst 4-speed. No Power Brakes, Steering or Windows.
Thanks a lot, Yea, I was looking at it and will pull it out and have a good shop go through it will heavy springs, etc. Does anyone know of a good, resonable machine shop in the downriver Detroit area that does good work?? You can never be too careful. I have been burned a couple times and can't afford it anymore. I need a good shop to machine the block and re-assemble it and also go through the diff.
thanks again....this site is great!!
thanks again....this site is great!!

For your diffrential needs vist Fastcorvette.com Talk to
Alan. Very reasonable.You can pick what you want done. Exchange,rebuild your unit, Buy your parts form him and do it yourself. And he will buy good useable cores. And he is very prompt with service.
Alan. Very reasonable.You can pick what you want done. Exchange,rebuild your unit, Buy your parts form him and do it yourself. And he will buy good useable cores. And he is very prompt with service.

Former Member
Send PM
, - USA
Joined: 11/8/2003
Posts: 21
Vette(s): 1971 Convertible, black on black with white top.
454, Hurst 4-speed. No Power Brakes, Steering or Windows.
Thanks, just got back in town. Yea, I spoke with Alan and he seems like a square fellow. Sounds good to me, thanks,
Ron
Ron

in Forum: C3 Driveline Components
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