Hey Everyone,

Sorry to ask what I am assuming is a common question but I have searched and found many different answers and my truck came without an owners manual.

1998 Dodge Ram 1500 4x4 5.9 Laramie with 3.55 Dana 44 front Chrysler 9.25 rear
Switching fluid in both differentials and wanted to ensure I pick up the right fluid.

Front: 75W-140 synthetic oil
Rear: 80W-90 standard oil

Thanks,
Patrick

 

Are they limited slip or open?

 

It gets a little cold in Wisconskin, right? I'd go with 80/90, you can probably find synthetic in that weight, btw. Use what the truckers use.

 

I just use what Chilton's recommends:

75/90 in front
80/90 in rear with friction modifier

all Valvoline dino. I'm at over 205k and no issues.