I have a 2000 4x4 blazer with a gu6 rear end that the pinion bearing locked up. DH is not sure about fixing that so we are looking into swapping out the whole diff. Can we swap that with a g80?

 

Yes, but the gear ratio has to match your front diff. G80 is the code for gov lock posi diff. GU6 is code for 3:42 gear ratio. Make sure the donor diff. has 4 wheel drive and GU6 rpo code as well as G80.

Caution, a 2wd donor will be narrower than your 4wd and a zr2 donor will be wider.

 

Thanx, next question is how do I tell what ring gear size 8.5 or 7.62 ? I called dealer and gave vin # and they said they couldn't tell.

 

The 8.625" is the heavy duty diff. standard in the zr2 package. Since your pinion bearing failed, I assume you have a 7.625". Those numbers are the diameter of the ring gear. To be positive about yours, measure from the top to bottom of the cover between the bolts. If it's 8 inches or just under, you have a 7.625".

 

From middle of the bolt hole to the middle of the opposite hole is measuring about 8 3/4" so I guess it would be 8.5----It also has the "ears" that diff wizard shows. It,s not a zr2 or a 5 speed, that's what bothering me. I read in other posts that 8.5 are used on zr2 or if you have a 5 speed.

 

You measured center of the bolt holes and got 8.75" not enough clearance for an 8.625" ring gear. You have a 7.625"

 

Ok thanx!