Sydwayz

GT4 is 3.73
GT5 is 4.10

bobonthis

I went that route and just went to the junk yard and bought a whole new axle for around $200 with the gear I wanted and then bought a hypertech computer to reset the speedo and the shift points. Like they said look for the smaller motor trucks they will have the bigger gear I had a 2wd s-10 blazer v-6 that had a 342 maybe I found a 4 banger s-10 that had a 410 worked out perfect.

articfriends

If you like the truck then rebuild and re-gear the axle for your needs. The 89 and newer chevy 1/2 tons used a 10 bolt 8.5 inch rearend with 30 spline axles. Gm cut corners when they made it a 30 spline by just boring out the old 28 spline casting on the differential case. They are prone to breakage(the side bearing shears off the case,usually on passenger side),the factory gov lock posi (which i doubt you have if its 2 wheel drive) also breaks quite easy. When I rebuild them at my shop I use a heavy duty open diff case or a eaton clutch type posi,they both have a sturdier shoulder where side bearings go on. You could regear it and upgrade the differential at the same time for 750$ worth of parts and a day of your time if your mechanically inclined,Smitty

wannabe

Buoyhunter:

If your truck has a GVW of 7200 lbs you probably have the HD rear axle. The Differential will look different, wont' have the 2 notches the std. Gm axles do on the bottom at 5 and 7 o'clock.m This is a much stronger axle than the regular half ton axle.

The tranny is your other weak link- trailer only in Drive , NOT OverDrive ON THIS MODEL.

You have plenty of power with the 350 Vortec.

Wannabe

birdog

A Bullet is #8900 Dry, No trailer....Trust me...1/2 ton aint gonna get it around here. Sorry......

Gofastboater45

Front Side of the axel tube on tha passenger side is a series of numbers stamped into the housing that will tell you the gear ratio. You may have to "wire wheel" the area to see it as it usually gets covered up with grease & dirt, but it is there.... Ill try to find the link that will tell you & post it. Is for GM vehicles only.

This site will decifer all the GM "Spid Codes" located on the glove box door, & or the trunk lid of most cars> http://www.fl-thirdgen.org/rpo/rpo.html

This may work to decode the VIN of GM Truck, I know it works for cars for certain years. Tells you where it was built, etc....> www.nytmare.org/fiero/vin/decoder.htm

bouyhunter

Yeah, I was being "wishful".

bouyhunter

acccording to the sticker, the rear-end is a GU6 G80.

=
3.42 / limited slip posi.

OK - that puts me at 6500#'s

Gofastboater - thanks for the link, that helped alot.

Smitty, $750 would probably be worth it, thanks for the info and advice

articfriends

The 9.5" h.d rear end you speak of is a rarity in the 1500 series trucks from 80's and 90's,I have rebuilt the transmissions and rearends in at least 500 chevy 1/2 tons in last ten years and have only seen (2) 1500 series w/9.5" rear end. If buoyhunter has one in his truck other than the junk G80 gov-lock posi blowing up they are very strong rear ends,Smitty
I posted a picture zoomed in on a broken gov-lock drive gear,it is real common problem even in the hd trucks.

Rippem