Axle

[gmf6430]

I have a 1996 GMC K1500 6 Lug looking for the rear gear ratio, what is it? as I do not have the code.

 

[rzr6-4]

Mine is 3.73, don't know if there were other options available though.

 

[454cid]

Check the glove box for the SPID sticker with all the rpo codes.

Failing that, you could pay $5 and run your vin through Compnine.

 

[Cadillacmak]

In the 96 manual they list seven ratios in the RPO codes, so I am betting at least four of those were 6 lug options.

 

[Caman96]

Enter your vin here:

Free GM Vin Decoder | GMPartsGiant

Free GM VIN Decoder - Do a VIN lookup to acquire specific car information. Ordering exact-fit parts has never been this smooth and hassle-free on GMPartsGiant!

www.gmpartsgiant.com

Then make sure to click on “See More Details”. Gives you your whole build sheet.

 

[b454rat]

Pull the cover and check on the ring gear. Will have it there, should at least. if not, start counting lol.

 

[Cadillacmak]

If you don't have an RPO and cant look up the vin, see if there is a tag on the differential cover. If it has a tag it will state the ratio, if not you need to remove the cover and look for a stamping on the ring gear, if you dont have that, count how many pinion gears vs how many ring gears. 40 ring divided by 11 pinion = 3.73 gears

 

[Caman96]

He must have a vin. Link above should tell him. Unless someone changed the gearing.

 

[RichLo]

Oh come on guys, its not that complicated. Its either 3.42, 3.73, or 4.10, maybe different if somebody put in a junkyard axle but those are the common ones.

Jack up both rear wheels, put jack stands under the axle. With the truck in neutral turn the driveshaft by hand and count how many revolutions the driveshaft needs to make 1 complete revolution of the rear wheels. If its just under 3.5 revolutions, you have 3.42... if its about 3 and 3/4, you have 3.73... if its just over 4 revolutions, you have 4.10s.

 

[Schurkey]

He must have a vin. Link above should tell him. Unless someone changed the gearing.

Truck is 29 years old, no idea how many owners--and what may or may not have been done with the rear axle/gearing. The main thing he has going for him is that, being 4WD, it's way more expensive to change gear ratios because you'd have to change the front diff to match the rear. And THAT assumes that the truck doesn't lock-up in 4WD due to a ratio mis-match.

If knowing the rear axle ratio is important, pull the cover and look at the gears. GM gears will have the tooth count stamped-into them.