AAM Differential ?

[Turbo Terry]

So I’m going to change the gear oil front and rear . 2022 3500 srw ho aisin Amsoil 75/140 severe duty in the rear 11,5 or 12 ? 75/90 severe duty in the front 9.25. I think I have a AAM 12 in the rear. What’s the difference between a 11.5 and a 12. Do I need new gaskets or at 3000 miles will they be reusable or should I get some new ones. Amazon has lube locker gaskets free shipping . Also do I need limited slip friction modifier. My Amsoil does not have it in it

 

[AH64ID]

You have the 12” rear and do not need 75w-140 for how you use the truck, and with your winter weather I would strongly advise against it. 75w-90 is perfect.

You may or may not need the additive. I’d get a bottle but only add if you get chatter.

The gasket is reusable.