Cheers everyone,

I want to do some more maintenance work on my car and was looking into the manuals about the rear axle (differential).
It says to use that very special additive if the car is equipped with a limited-slip rear differential.

My car is a 2004 RAM 1500 quad cab, regular bed, with the 5,7 HEMI and the "AWD" system.
The build sheet says "CORPORATE 9.25 LD REAR AXLE", and "ANTI-SPIN DIFFERENTIAL REAR AXLE".

So, do I need the additive on that axle, or not?
And what oil would be the ones to use then?

Thanks a lot!

80/90 For regular use, 75/140 if you tow/haul a lot. Yes, you need the additive as well.

Thanks a lot!

Does it harm if I use 75/140 then? As I might be using a trailer in the next year more frequent, but not this year.

Nope. Won't hurt a thing.

I searched on the Castrol website and it showed me the "Castrol Transmax Limited Slip LL 75W-140" which says it has the additives added already.
Anyone tried that? Or is it a "rip off" and would it be cheaper to get a normal 75W140 plus the additive?

I think the 75/140 only comes as a synthetic..... but, not sure on that. If you get the stuff without the additive though, and add it yourself, then you KNOW that it has the correct amount.

I used the mobil 1 LS version in my 1/2 ton, worked fine.

Thanks for all your help, really not easy finding out what to use in that truck.

So for the front differential it says "Mopar Gear Lubricant 75W-90", but I only seem to find some synthetic gear lubricant.
Is it fine to use the synthetic gear lubricant? I found a shop that sells Mopar 68218655AC synthetic gear and axle lubricant (MS-9763).
Is that the correct stuff?

Thanks a lot!

EDIT: I found this helpful website and I think I finally found the correct oils now:

https://haynes.com/en-us/tips-tutori...aintenance-faq