Hey guys, i am helping a friend out and he needs to get a new rear differential for his 95 Jimmy 4.3L. I checked up on car-part.com and fond many choices as to which differential is in the truck... so my question is simply how do i figure out what ratio his rear end is?

 

Fastest way is through the RPO listing in the glovebox.
Here are some of the ones off of a 2000 list (don't think it changed at all year to year):
GT4 Rear Axle: 3.73 Ratio

GT5 Rear Axle: 4.10 Ratio

GU4 Rear Axle: 3.08 Ratio

GU6 Rear Axle: 3.42 Ratio

G80 Rear Axle: Positraction, Limited Slip

You could also look it up on one of the many RPO code listing sites: Regular Production Option (RPO) Codes

 

thanks buddy, very helpful! looked it up in there and it was a GU6, so we are good to go for a replacement.

 

ok sorry for the double post... just wanted to get your attention again... is there an option code for the ring gear size? 7-5/8 vs. 8-1/2?? if not, how do we find that out?

sorry for all the questions, im used to working on FWD imports and this is not really my comfort zone

 

I PM'd you back...

I believe that all 96-up blazers with the H.O. 4.3L (L35 w/ "W" 8th VIN digit) came with the 8.5" axle. ZR2's also came with 8.5".

Don't know if that is correct or not, but I remember reading it somewhere...