Dose the differential of a 4wd blazer fit my LS model?
I have a 2001 2wd blazer and just yesterday the differential went out. i want to replace it but i was wondering if i can replace it with a Zr2 4wd diff. with out having to do any other adjustments or modifications..
thanks.

 

I am pretty sure the 2WD and 4WD use different rear ends.

 

Width of the housing is the primary difference. The 4WD is wider than the 2WD and the ZR2 is widest of all. The 2000+ differential itself (center section) is the same, as long as your are working with the same size carrier. Your choices are 7.65" or 8.65" ring gear carriers. So if you use a ZR2 rear, it will bolt in but your wheels will stick out abnormally.

You just need a complete rear out of a 2000+ S10 2WD or 2000+ Blazer 2WD. Older ones might fit fine (7.5" or 8.5"), but driveshaft might not be right. Of course if you take the driveshaft too and it's coming out of a 2WD Blazer then no problem. If you have a 5-speed trans behind a 2000+ 4.3 then you probably have one of the few 8.65" 2WD rears - everything else in 2WD should be a 7.65". Look on glove box door for same rear end ratio code when you look for a donor vehicle. Stay away from 4 cyl S10 5-speed manual OD transmissions unless you want open 4:10 gears.

Make sure you can get the fill plug out of any rear you want to use, before removing the assembly from the vehicle.

GU4=3.08
GU5=3.23
GU6=3.42
GT4=3.73
GT5=4.10
G80 : AXLE POSITRACTION, LIMITED SLIP

 

Does the ZR2 use a 8.5/8.625 ring gear? If so then isn't the carrier larger than one that uses a 7.5/7.625 ring gear or are the carriers the same size and the difference is just the ring gears?
Does the spline count go up with ring gear size?

Just trying to learn about the differences in GM differentials.

 

Not sure that Zr2 are all 8.5/8.65 but I do know they are a lot more common in 4wds. i have only studied the 2wd S10 rears. The 8.65 and 8.5 s10 rears can be identified by the axle tubes. They step down in size after coming out of the center. 8.65 cases have bigger carrier bearings than 8.5 and have 30 spline axles instead of the 28s found in the 8.5. You can put an 8.65 carrier in an 8.5 housing with an adapter bearing but not vice_versa because the bearing does not exist. Fortunately aftermarket carriers like Eaton are made to the 8.65 bearing spec so aftermarket will fit in either housing. Aftermarket carriers in both 8.65 and 8.5 housings use the aftermarket 8.5 ring and pinion. I haven't studied 7.65 vs 7.5 because I don't care about the performance aspects of them. I believe the old 7.5s are all 26 spline axles. Certainly the housings and carriers are different than in the 8.5 / 8.65

 

Ive had an s10 and now have a zr2. The s10 was 7.5 and my zr2 is 8.5

 

I did not measure the ring gear when I had the cover off awhile back, just looked small so I thought it was the 7.625"...sure hope so as that was the used G80 Yukon diff I bought. Guess I will find-out once I remove the open carrier.....

 

My 2001 LT 4wd has the 7.625.

Here's the s10/Blazer 8.625. note the step down on the axle tubes and the sharp points on the bottom of the center

https://www.drivetrainshop.com/v/vsp...le_gm_85_2.jpg

 

Lesmyer: well the picture above is exactly the same as the diff in my '02 4dr 4wd. So it is an 8.625" ring.
Now I am wondering if the G80 carrier I bought will work with the larger ring gear. How can I find-out without taking it apart?

 

if you have the step down axle tubes like in the photo then you have an 8.625. a 7.625 carrier will not work in an 8.625 housing. A factory 8.5 carrier will not work in an 8.265 housing either. Aftermarket "8.5" carriers are really made as 8.625 carriers so they will fit in both 8.5s and 8.625s.