well i am looking for a spool for my blazer, it is a 91 2dr 4wd with a 4.3 in it. i need to know what rearend i have and also what front i have. do they make a spool for the front? im thinking about welding the front and rear diffs up, but since i see spools are like 85 bucks, i would go that route instead. this truck is a 100% offroad truck only, so spools or being welded it will be fine :D

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

You can probably install a mini spool to save a few bucks. Weld the side/spider gears like you said. Drop in a lunch box locker for the front.

yeah, you posted that in my other topic, but i was looking for what rearend does it have? like on my ranger i have an 8.8" rearend. im looking for a mini spool but dont know what diff to look for.

Should be a 7.65" rear axle. Whereever you go to buy the spool, will be able to verify the axle.
Let me know what a spool costs. I want one for my rear axle in the '87.

Ahhhh. .OK, you didn't specify, inches or gear ratio.

I have a 7.625" (7 & 5/8") rear end, 7.25" up in the front. Not sure if they changed the size over the years.

sorry for not being more specific from the get go. thanks for the help guys im gunna check around for a spool and what not. if i find a spool that fits a GM 7.25" would it matter if it is in the front or rear? did GM ever put a 7.25 in the rear? the more i think about it, im not gunna do that to the front of this truck, especially not yet....may cause to much problems with the turning....

the closest i can find on summit is a GM 7.5" [&o]

after more looking, some sites say the 7.5" spool will fit the 7.625" rear. others dont say....anyone know?

I think they're the same. I looked up some info on it and here's what I found.
Do you have IFS?

Vehicle Model Year
S-SERIES PICKUP, & BLAZER 79 & UP


(OEM) GM 7.25" FRONT RING & PINIONS
TEETH RATIO

40-13 3.08
41-12 3.42
41-11 3.73
41-10 4.10

GM 7.5" & 7.625" RING & PINIONS (rear)
TEETH RATIO

OE 41-15 2.73
T/L 40-13 3.08
OE 40-13 3.08
OE 42-13 3.23
OE 41-12 3.42
T/L 41-12 3.42

Try here for rear end stuff.
http://www.wayfindersband.com/powertrax.html

yeah, i have the torsion bar suspension. i have the no-slip in my 2wd ranger and ABSOLUTELY LOVE it. it is awesome onroad and especially offroad, maybe ppl have thought i was 4wd when im only a 2wheeler, lol. as for that link. i see a powertrax for 99.99, but how do i get more info on it? there isnt a link anywhere, that i see atleast...

Here ya go.... (http://www.powertrax.com/nsapplications.html)

They claim their LockRight is a little noisier than the powertrax. The lockright is about 95.00 cheaper. Whats nice you don't have to mess w/ pinion/ring gear backlash. It's a drop in and play.

yeah, i installed my no-slip myself, took less than an hour :)

Less then a hunred bucks. Not a bad price.
Thanks guys.

GM used three different sized rear axles in the S10's.
7.5"= original size
7.625"= newer size, I don't know the year break
8.5"= ZR2.

Check out the Aussie locker too. I hear they are even better then those two lunchbox lockers.