1964 Rear Dana 44 Rebuild
 

Hello all,

I'm working on rebuilding the rear differential on my '64 GMC. I've got it off the truck, cleaned up, and stripped (bearings, racers, seals, etc). I'm on a budget and I've never done this before, so I'm looking for community advice. The pinion gear looks pretty chewed up to me, but the o-ring gear looks great. I don't want to spend the money if I don't have to, but also don't want to have to do this again (rebuild the rear). I plan to use this thread for all my future questions as well, but here are the ones I have at the moment:

1. Does the pinion look too chewed up to you guys?
2. These things are pricier than I'd like, is there a way to buy just the pinion gear and not the o-ring too?
3. If I have to buy new, should I drop down a ratio for better highway driving? The engine is the 3.8L 230ci and the current diff ratio is 3.54.
4. I hate spending more money, but would it be worth it to put a limited slip in while I have it a part?

Thanks for any advice you can offer.

-Jared

Re: 1964 Rear Dana 44 Rebuild
 

The 4x4 Jeep crowd likes Dana 44/60’s, parts for them are a little pricy. You could swap to a 12 bolt. Captn fab will have the mounts for you.

https://customfab-cda.com/?fbclid=Iw...LTEqsVip-IhLFo

Re: 1964 Rear Dana 44 Rebuild
 

Both of those gears are toast

Re: 1964 Rear Dana 44 Rebuild
 

1.Does the pinion look too chewed up to you guys? YES
2. These things are pricier than I'd like, is there a way to buy just the pinion gear and not the o-ring too? NO they are a match set.
3. If I have to buy new, should I drop down a ratio for better highway driving? The engine is the 3.8L 230ci and the current diff ratio is 3.54. 3.07 would be better for highway driving.
4. I hate spending more money, but would it be worth it to put a limited slip in while I have it a part? NO $$$

3.07 P/N 2408337
Pinion gear stamp 31492 14 tooth
Ring gear stamp 30060 43 tooth
Used 3.07https://www.ebay.com/itm/36442618961...Bk9SR5iRhtPsYw

706017-1X Differential Ring and Pinion Kit 3.07
https://www.dennysdriveshaft.com/p41...3.07_rati.html


Custom fab only has mounts for trailing arm equipped trucks. GMC went back to leaf spring in 63.

Re: 1964 Rear Dana 44 Rebuild
 

You're in the wrong hobby

Re: 1964 Rear Dana 44 Rebuild
 

Lol

Re: 1964 Rear Dana 44 Rebuild
 

Thanks for the helpful comments.

After watching a few YouTube videos, I better understand why this pinion is far too gone. I'm thinking the people who rebuilt it the last time didn't do the proper heel/toe adjustment. It would be noisy even if didn't slip. I'll be buying a new set. For future reference and others who might need an education on rear diff anatomy, here's a video I found super helpful: GM 10-bolt axle rebuild complete!

I'm planning on keeping most of the truck as close to original as possible. It's got the "4 on the floor" transmission with granny gear and this open face D44 (no limited slip). With this in mind, I've read that going to high in diff ratio can really reduce the torque. To keep a happy balance between highway and rear wheel torque, I'm wondering if it would be best to stay at 3.54. Does anyone have experience with this?

Re: 1964 Rear Dana 44 Rebuild
 

You will need the 1962 GMC maintenance manual X6223.

Here is a video for the Dana 44. Dana 44 Axle setup

Re: 1964 Rear Dana 44 Rebuild
 

Thanks, gmc jr van!