I am going to be doing a lubricant change on the transmission, transfer case and the front and rear differentials. Is synthetic the best way to go? What about the friction modifier for the rear? What brands are good? Am I going to have to do a second mortgage?

 

Go to Dodge and get the Mopar Modifier. It should take about 3 for the rear if you have a Dana 70 and 2 for the front on a Dana 60. Mopar brand is the only one that will work 100%. Have fun it's a big mess Dodge Trucks are the only truck I have and will ever run trust me get the Mopar Modifer

 

From everything that I have read, synthetics are the way to go because they help so much with heat and they do not break down like the regular fluids. I have Mobil 1 in my tranny and both diffs and have had no problems. Alot of guys run Amsoil, Redline, etc. I am sure that you will get alot of different opinions here. Good luck.

 

I run synthetic in everything I can and no modifier in the LS rear. It works fine on mine.

 

When the truck was new it had a rear end problem which required it to be overhauled. They forgot to put in the friction modifier and it chattered really bad in sharp turns. Also, as I understand it, the rear diff is the only one requiring the modifier. Is this correct?

 

Yep.

 

I use my 4x4 alot at the ranch and since my front axle is a posi- I put the modifier in

 

Amsoil fore an aft here...4 years +

 

If you go the Amsoil route the friction modifier is not usually needed, though Amsoil just came out with a new product called Slip Lock that can be added to any gear lube to eliminate chatter. It comes in 4 oz bottles and treats differential with 2 to 4 quarts.

On the ATF, I've seen temperatures reduced 20-50 degree while towing and other high load applications.