64 cuda original rear end

[Garry]

wow a 7 &1/4 posi, must have been an option, dads car bought new ,know it's original. was there a special gear lube for this animal? also anyone know where I can find 1.5 front bearing caps?

 

[DonPal]

NAPA has a GL-5 API Service rated gear oil 80W-85W-90 that is for limited slip differentials. They also sell a "friction modifier" that is intended for limited slip differentials.

I used both together in my 65 Dart 7 1/4 suregrip differential after rebuilding it with new bearings & seals & adjusting/tightening the pinion/ring gear backlash to specs by replacing the spacers.

I'd recommend you pull the cover, clean things up, & check the backlash before investing in the fluids.

Is your pinion seal leaking?.....another item to fix before investing in fluids.

 

[Garry]

yea DonPal did all that am ready for fluid now Thanks for the napa hook up.

 

[Charrlie_S]

How about a 7 1/4 Sure Grip 3.91
7 1/4 SG 4.56
7 1/4 SG 5.13
All in stock, the 3.91 is in my 66 Valiant

 

[Tadams]

How can you tell if you have a sure grip or not? Mine is in a 65 Formula S.
Thanks, I'm still learning

 

[DonPal]

If the rear is in the car use a floor jack under the center and lift both tires off the ground; spin one tire and watch the other tire:
1) if both tires spin in the same direction it's most likely a suregrip
2) if the tires spin in opposite directions it's not a suregrip.

Most suregrips have a special suregrip lube plate bolted to the rear

 

[Tadams]

Thanks, I'll check that.