I've got an 88 GMC Sierra 1500 4x4 truck and I am tired of the single rear tire spinning all the time so I found a 6 lug, G80 posi rearend with drum brakes out of a 97 Chevy 1500 4x4 truck that I want to use.

Its got 3.73 gears just like my truck. It seems to have heavier leaf springs on the rearend than my truck has (5 leaves vs 4) and I am wondering if I can swap the rear with the springs into my truck.

Is this a direct swap or will I need to cut off and relocate the spring perches and shock mounts?

And if I do have to relocate the perches, what should the pinion angle be set at?

One thing I noticed is the donor truck has an aluminum driveshaft but my truck has a steel one.
Is there a special conversion universal joint that will be required for this swap?

Is the length of the existing driveshaft still gonna work?

I haven't removed the rear from the donor truck yet. Are there any other items that I should grab while I am under there?

Here are a few pics of the rearend that I am getting.

 

You're in good shape since you're swapping from similar truck to truck - GMT400 to GMT400, and both are 4x4 half ton.

You can absolutely swap the spring packs over and I would do that. Be sure to get the u-bolt plates from the 14 bolt as they're different to fit the slightly larger axle tubes.

It's a bolt-in for you, everything is in the same place. About the only real concern is you may need a conversion U-joint, most likely will; the #'s have been posted a lot of places and I don't personally have the # in memory.

Before buying it, pop the cover and be sure it's the right gearset. People change things out. This will also give you a chance to check the general condition of it, look for metal chunks loose inside the case, etc. If you didn't already know, you can easily check the gear ratio by looking for the numbers stamped into the edge of the ring gear -



In that example, see the 41 and the 10 - divide the large number by the small one, 41/10 gives you a 4.10 ratio.

Also, the G80 unit in the trucks isn't a posi, it's a locker. Be 100% sure to not use any posi type additive to the gear oil. Run straight gear oil, otherwise the locker will not work correctly.

Richard

 

Also Inspect the gears for wear as well. Than inspect the pin that slides into the center to keep the axles separated. It's not un-common for the bolt to snap or the pin to wear in the bore causing damage.