62 posi

[Todd Pollock]

I am getting ready to swap the rear in my 62 from a 4.11 to 3.36 so I can do better freeway cruising. Any particular tricks or other things I need done at the same time. I have a whole new unit to put in, not trying to change gears in the old one. Already replaced wheel bearings a year ago.

Thanks

Todd.

[Denny Jacobs]

Re: 62 posi

If the posi clutches were replaced in the new unit you are installing, confirm with whoever rebuilt it that one of the plates on each side is .060" thick. The other are all .090". The shop that built mine didn't know this and I had to remove the chunk and rebuild it again. The extra .030 on each side would not allow the diff to work independently.
Don't forget to seal the bolts that hold the chunk to the axle housing.
When I changed gears in my '62, I also added a drain plug in the bottom of the axle housing.(I think that '62 was the first year to delete the drain plug.) I used JB Weld to glue an 1/8" plate on the INSIDE then drilled and tapped a 1/2"-20 hole through the housing and plate. An engine oil pan plug works nicely. I pre-drilled 3/8" holes in the housing and plate and used a 3/8" bolt to hold the plate in place while bonding with the JB Weld. Pour JB Weld around the edges of the plate and not between the plate and housing. It would be too easy to "weld" the 3/8" bolt in permanently.
One more thing, test fit the axles into the chunk on the bench to be certain that the splines on the posi clutches are lined up. This should have been done when the diff was rebuilt. Check it to be certain, otherwise the axles will not install in the housing.
Good Luck,
Denny

[Richard E.]

Re: 62 posi

Todd - At some point you'll also have to change out the speedo gear to accomodate the big change in the rear end ratio. Might wait until you get it on the road to see how far off the speedo indicates. Doc Rebuild has speedo gears.

The idea of adding a drain plug (if you don't currently have one) is good for convenience. But for judging, if that's a goal, after approx S/N 1500, there was no drain plug. Could probably stretch tha to S/N 2500 or so. But its a pain to drain by having to loosen the pumpkin. Regards....Dick