I want to change my Diff fluid on my 4x4 08 Ram this weekend, but i am reading a lot of conflicting info on here and would appreciate some clarification.

1. Some say 75W-90 for front and 75W-140, some say 75-140 for both.
2. Some mention the necessity of the Friction Modifier Additive for the rear while some say Synthetic gear oil already has it.
3. How do i know if i have the LSD differential ?

Thanks,
Pete

 

If stock / you do ! imo. your manual says 90 weight in the front and 140 in the rears. Yes it is necessary for the lsd to work properly and yes ,most synthetics already have it in. for the application I went with vlvoline, A good synthetic and has the modifiers added per the web site btw, most labels say it is included in their respective products. Double check with the mfg. and get a dealer build sheet on your truck it's free that will say everything that is put in the truck. good luck and welcome too df.

 

I appreciate the info Rocket.

I did both diffs... I used ~2qts of 75W-90 for the front and ~2.3qts of 75W-140 of Valvoline Syn in the rear, sound right ?

Thanks,
Pete

 

Sounds a little low in both area's Did you put your finger in the refill hole to the first knuckle and feel oil when refilling? And did you pump the oil out or crack the pumkins? what did you find? And lastly where are the pics??
ps. glad I could help (at least one person here) CC. too A.m. and Rh.

 

what kind of rvt silicone should you use to seal the rear end? i found 2 different ones.. one good to 500 degrees and the other to 650 degrees.

 

any red or black RTV ..--which ever is cheaper of the 2. diff doesnt get that hot