The Stovebolt Site Forums The Shop Area Engine Shop Posi for old Chevy trucks?

I'd dearly love to have a posi or limited-slip differential for my '59 Chevy Apache pickup. I'm told that nobody makes such a unit for old Chevy trucks. Anybody out there ever try to see if anything would fit this removable third-member rear axle?

Never seen one for the HO-33 dropout axle, but the '59 1/2 tons had a posi(or limited slip) option. It was a Dana/Spicer type rear axle like the GMCs were using though.

Is the truck a 3/4 or 1-ton? If so, Detroit Locker used to make a locking diff for that center section, and I've heard rumors that there might be a few posi units floating around. I just got one of the lockers from eBay. There have also been a few listed in the swap meet - keep your eyes open.

I've got an Eaton Locker in my '63 that is indestructable. They are really built heavy and has never caused me any problems.
Scott

Well, this is a 1/2 ton truck (3200 series). So, does this mean there's a posi out there somewhere just waiting for me? . . . if I can find it.

It's easy enough to convert to a 12 bolt out of a 67-72. I'm not 100% sure the wheel bolt patterns are the same but I think up through 1970 they are. After 70 they went to the 5 lug wheel.

Boo Radley

Well, actually, Boo, when I got the truck it had a late '70s 12-bolt rear axle. I got a stock '59 Chevy truck rear axle for it which has a 3.90 gear ratio, which is perfect for me, since the late '70s 5-bolt axle has a 3.07 gear ratio, and my 700 R4 tranny has a 30% overdrive, and a 3.05 1st gear. So, yeah, if push comes to shove and I really have to have a posi, I can always go back to the 12-bolt axle and get a new ring and pinion while I'm at it. But I really like that 3.90 ratio.
Does any body need the 235 six and grandma 4-speed floor-shift I took out of it?

I used a Dana 44 limited slip with 3.55 gears and 6 lug drums from a '67 GMC in my '59. It worked really well in mud and snow when in the GMC with a 305 v-6, but I'm not sure it would be stout enough if you're building it up for drag racing. Pretty easy swap. I had to weld up spring perches, re-locate bracket for the brake line tee to the left side, and adapt the ends of the park brake cables to work with the backing plates. Used the original '59 lower shock mounts that fasten on the bottom of the u-bolts. Haven't drove it yet though as the rest of of the truck is still under construction.

I'm not sure what rear end you have, but the bolt pattern from at least the '37 trucks up to our '94 chevy pickup all have the same bolt pattern. If you get a rear end from a pickup from the late 60's or 70's, make sure it comes out of a 4wd. Otherwise it will have the 5 lug axles.

welder + a case of beer = posi-trac

if you were realy going to take it out to the drag strip alot, it might be worth it to swap back to GM 12 bolt. you could get a brand new 4.10-1 posi unit for arouind $500 but you could count on it to last for wile