Rear end questions.
 

Hey guys, I've got my '83 GMC Suburban K2500, and I'm not sure how to find what rear end ive got (without counting the teeth on ring and pinion). I don't have the truck with me at the moment (I live in Ohio for school, truck is home in Vermont until next month when I get it out here). And I'd like to see if I've got 3.73's or 4.10's. I've got the VIN: 1G5GK26M8DF517698. And the option sticker from the glove box. Any help is appreciated, if there's no way to find out using this info, just tell me and I'll physically check the teeth when I have the truck with me again. Attachment 1638616

Re: Rear end questions.
 

Interesting!

Did some looking and your RPO code "GQ1" means the standard axle ratio given the engine/tranny/and federal or CA for that year. So, not really easy to tell unless you take the cover off.

Looking at this chart (pdf) and your tranny (MX1), looks like 4.10.... page 6.
https://www.gmheritagecenter.com/doc...t-Suburban.pdf

Re: Rear end questions.
 

I've got that same PDF saved on my phone, I'm pretty sure I am running the 4.10's with my Turbo 400 (I believe it's an NP208 T-case as well). I'd assume I've also got the same ratio in my front axle as well? That may be a dumb question but I'm not 100% sure. (Still learning)

Re: Rear end questions.
 

Once I get my truck back to Ohio I've got to take a closer look at the front axle too, pretty sure it's either a Dana 44 or 60, and judging by the way the fire dept. ordered the truck, I'd put some money on the 60.

Re: Rear end questions.
 

Yes, both axles will have the same ratio. Otherwise, it would bind and not move in 4wd....have to match.

I pulled front axle off of a 89' 3/4 ton suburban...was a 10 bolt (Dana 44 equiv). I'm guessing you will have a Dana 44, but who knows! :) Maybe you get lucky!

I'd say you have NP208 transfer case.

Re: Rear end questions.
 

Was able to have my dad check the front end back home, Dana 44.

Re: Rear end questions.
 

Nicely done. Looks like my work here is finished -

K

Re: Rear end questions.
 

Hey Country, did you get the chance to figure this out? I'm curious, because I have a 1982 2WD Suburban with the trailering package. It has the MX1 transmission and it calls out the 4:10s as option GT5 on the SPID. I see you have the locking diff which I wish I had.