So i'm curious, my rear end is going out and when i'm looking up parts there's multiple options. When i asked dodge they said the rear end ratio is 3.55, so my next question is how do i tell if i have a 10 bolt or 12 bolt rear end. How do i go about finding out. As well as splines on the axle shafts. Hope everyone can help me.

 

So far as I know, it's a 9 1/4 with 12 bolt cover. 3.55:1 was the standard gear set. Axle spline count? It's hard to believe there were different counts on 1/2 ton pickups, why doesn't the Dodge dealer know this? Try giving them your vin. I'd hit up the boneyard before the dealer either way.

 

I Agree with 4 speed.....

Looks to me there are 2 options...
8-1/4 Ring gear Dia... With a Ratio Option of 3.21 / 3.55 / 3.90
OR The
9-1/4 Ring Gear Dia... With a Ratio Option of 3.21 / 3.55 / 3.92
There Might Be an I'D tag mounted on the housing or cover bolt.
If not you have to pull it down to see what you have for a ring Gear Dia. and go from their.

Hit Up Budget First. Up in your neck of the woods..
See if they have one you can swap out...
http://www.budgettruckwrecking.com/

If not... Call Doc. Diff....
http://www.doctordiff.com/

Hope this helps....