You guys know what gear ratios were offered on Blazers, maybe you can tell me what I have.

No tags to be found on the diff. So 1 full revolution of the tire is equal 1 3/4 turns of the pinion yoke.

vehicle has just over 100K miles on it. The pinion had play in it and it was leaking. Aside from the high pitched whine. I just rebuilt the rear last weekend. With this small of mileage on this rear I was surprised to see someone had already been inside (Non factory silicone gasket on the Cover).
It wasn't going back together well it had a binding on the pinion as I torqued down the Carrier Caps. Anyway after getting it in and feeling very good.. 200 miles later the thing sounds like crap. I think either the Axle housing is messed up or maybe the carrier got bent by the previous owner... anyway, I 'm looking to just throw in a new/used rear. $200 worth of bearings/ Races and seals to go in the garbage.. bummer

 

Look in the glovebox for the RPO code sticker. You should see something like GU then a #. Once you have that code, it will tell you what the ratio is. For example my 2000 has the GU6 rear which is the 3.42

 

GU2:-:2.73
GU4:-:3.08
Those two are more often in larger trucks and not normally seen in s-series vehicles.
GU6:-:3.42 Very common ratio for 2wd and 4wd
GT4:-:3.73 Came with some tow packages and factory in the ZR2's
GT5:-:4.10 Came in the blazers and maybe the s10's with 4wd and 4 cyl engines

and as a bonus...

GQ1:-: open rear carrier
G80:-: Eaton designed posi traction unit. Hope this helps!

 

I'll check the Glovebox...

The VIN number? is the Gear ration in that number?

 

No, not in the VIN.

 

I wet to the Chevy parts coounter and the cool guy printed 2 pages of the RPO codes all he needed was the VIN

 

yes davedidit, the VIN will tell you every option that came on your truck.

Richard (rriddle3) isn't wrong, it's just that you can't "find" what gear ratio is in your truck easily with the VIN-unless you're standing @ the dealer.

with the RPO, you can simply look them up yourself, or have Joshua just post them up for you (much like he did above ).

 

wow I always thought i had 3.73 gears but it seems I actually have 3.42 looking at the rpo codes, no wonder I'm getting crappy gas millage. I also learned my blazer is in fact a z85... don't ever know why I didn't look at those before.

 

Time for a gear upgrade. lol

 

Actually, you can find the gear ratio from the VIN. It just isn't part of the VIN, but rather, needs an application to look up the RPO codes for that VIN. CompNine.com has such an application in their VIN Decoder.