Rear axle interchange?

[65standard]

Does anyone know if a 1999 suburban rear axle is the same width as my 1985 C/10. I see it has the same 5x5 bolt pattern. I'm looking for a rear axle with 3.73 posi for my LS swap.

[Rangerman]

Ive been wondering also---

Im wanting to swap the 3:08 open end gears in a 79 to 3:73 with posi.

[Speeding Dakota]

Originally Posted by 65standard

Does anyone know if a 1999 suburban rear axle is the same width as my 1985 C/10. I see it has the same 5x5 bolt pattern. I'm looking for a rear axle with 3.73 posi for my LS swap.

Yes the axles are the same. I put a 3.42 posi out of a 90 burb under my 83 C10.

[68c10owner]

Originally Posted by Speeding Dakota

Yes the axles are the same. I put a 3.42 posi out of a 90 burb under my 83 C10.

A 1990 burb is a different body style than a 1999 burb.

I beleive the 1999 burban will be wider than your truck rearend. THe spring pads may also be in a different place which isnt a big deal and the brakes may be different. It will work but there will be some differences to take into account.

[69heavychevy]

It's not bolt on, different widths...
BTW GM production "posi's" don't hold up very well. Best bet is to add aftermarket gears and posi unit.

[Gregski]

Originally Posted by 69heavychevy

It's not bolt on, different widths...

I recall reading the same thing on this forum somewhere too, different widths, think the Burb is wider

[KQQL IT]

Originally Posted by 65standard

Does anyone know if a 1999 suburban rear axle is the same width as my 1985 C/10. I see it has the same 5x5 bolt pattern. I'm looking for a rear axle with 3.73 posi for my LS swap.

http://67-72chevytrucks.com/vboard/s...d.php?t=373438

[65standard]

I'm going to the junkyard now to measure the suburban' s rear axle.

[65standard]

The 1999 suburban rear is 65.5" drum to drum.
My 1985 C/10 rear is 65" drum to drum.

[68c10owner]

Originally Posted by 65standard

The 1999 suburban rear is 65.5" drum to drum.
My 1985 C/10 rear is 65" drum to drum.

So its only .25 wider per side but the spring perches and shock mounts are in different locations. And the oem posi isnt very strong.

[65standard]

It might be a bolt-in rear. It has dual spring perches on each side. The inner perches might be for the earlier narrow frame?

For my situation, I'm going to cut off the spring perches anyways as I'm doing an axle flip.

[65standard]

My other choice is this 1990 blazer rear. Direct bolt-in, but it is a 6-lug wheel.

I did snag the blazer's cluster I needed for my LS2 swap and the tilt column.

[Gregski]

good info ya'll