Rear differential leak in 63 CDV

So my 63CDV has leaking rear differential !

I've already ordered the gasket but cant find the seal! Any help?

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Comment by Tony and Ginny 429 on March 31, 2015 at 9:46pm
In general best to get the place were you think you have a leak,as clean as possible and inspect the area very carefully to be very sure you identify the leak location
Do consider that to much play in your pinion gear could be possible for the seal going bad which means the rear end housing could require replacing
You will only be able to inspect the wear that may have developed by pulling the rear end housing and checking it ,off the car I would think
You can determine the wear on the teeth of the ring and pinion by inspection
The play in the carrier bearings and pinion gear may be in question
If you replace the seal and it holds for you that would be wonderful
I once replaced the ham gasket without taking the ham out of the car
I cut the gasket at its very top and removed the inner part of each bolt hole so I could slide it between the rear end housing and the ham
You need to loosen all the ham bolts and pull it to you
After all the fluid is out ,you can slide the gasket in place between the axel housing and the ham and bolt it back together
The rear end ham in these cars Cannot be repaired--if it has gone bad ,unlike many other car rear ends
You need to replace the whole ham
Gear ratios would be a consideration at that point
Comment by Jason Edge on March 31, 2015 at 9:00am

Excellent reply from Tony covering all the bases! I will add this to our Help Topics page.

If you end up needing a pinion seal, I have new ones in the box for $20 + s/h. Shoot me an email to if you need one.

Comment by Tony Albarella on March 31, 2015 at 8:40am

The '63 has a sealed differential that, according to the shop manual, does not require fluid changing until or unless it is disassembled for repair. Of course, those recommendations did not take into consideration 50+ years of fluid use. The key to fixing a differential leak is, like any leak, first finding its source. Here are the potential sources:

1) If it's leaking on the ends near either tire, that's the seal that needs replacement and will have to be accessed by disassembling that side of the axle hub.

2) If it's leaking from the very front of the carrier (where the driveshaft connects), it's the pinion seal. I recently fixed a leak from this area in my '63. It's a common problem as the rubber seals dry out over the decades and allow fluid to bypass them. It requires a disconnection of the driveshaft, removal of the pinion flange and nut, and prying out then replacing the pinion seal.

3) If leaking from where the pinion extension bolts onto the carrier, you've got a slightly more complicated job ahead of you. Here's a link from another blog with good advice on trying to torque the bolts with new copper washers before resorting to disassembly:

4) If you're lucky, it might just be leaking from the fill bolt. Easy fix with a new washer gasket, unless the threads are stripped, which might require recutting the threads or sleeving the hole.

4) If the carrier is leaking due to a crack or compromised area, replacement of the whole unit will be necessary.

Be sure to thoroughly clean the entire area and refill to determine the exact area of your leak. Once fixed, regular differential fluid replacement is highly recommended and possible by pumping the old fluid out of the filler hole. Good luck, and let me know if you need more details or photos of the pinion seal replacement.


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