Rear Axle Codes
 

New to me 2002 Blazer and I'm going over it. After a search here I got these codes off of the glove box sticker and want to know what for rear axle is in this thing? GT4 and G80 are the only two 'G' codes on the list. The rear axle cover is rusted through to the point that it is leaking so I'm in the process of replacing it (new one on the way, old one is open and draining out). So...what does it have and can I verify it by looking at the gears in there?

Thanks,
Mark

GT4 indicates that it is a 3.73 ratio
G80 indicates that it has the automatic locker in it

Most likely it is a 7.5 ring gear as that is the most common on these, but you can tell for sure by looking at the diff itself. The tell-tale sign between the two are a pair of protrusions on the bottom of the center section.

https://cimg7.ibsrv.net/gimg/blazerf...4e8bf8be18.jpg

Thanks for that! Based on that it's the 8.5 in the middle. Seeing as there are that many options, I hope the cover kit that I receive is the right one. It looks like the 8.5 and the 8.2 could use the same one and that bolt pattern matched the one in their picture.

Do like Dodge did- put a big magnet on the inside of the diff cover to catch metal particles. If that's like my 78 locker, a part breaks off and slings metal fragments around and wrecks the whole unit

There is a magnet fastened inside the cover and I wonder if one could place a super magnet on the outside of the cover if there was none on the inside.

You’re sure about the GT4? What model Blazer do you have?

Yep, I's sure. Not sure about the model (it is new to me yet), does LS sound right? It seems loaded, heated seats, seat position memory, electric mirrors. 2002 MY. And it is an LS rear, I had to replace the rear cover and saw extra stuff in there. Then I tested it with one rear wheel off the ground.

The reason I asked was that it didn’t sound familiar to me. I knew zr2 had the big rear with that ratio, but after searching found a old forum post that states that ratio was available in certain tow packages:

https://blazerforum.com/forum/steeri...999-4wd-46921/

Thanks and interesting. What all goes into a tow package? There is no hitch on this vehicle and the trailer wires are still tucked up in behind the bumper (I think that's them).

Here’s something else you may find interesting, inside you’ll find how to identify axle ratios by the code stamped into the axle tube:

https://www.gmheritagecenter.com/doc...let-Blazer.pdf