My brother-in-law just picked up a (new for him) 2009 6.4L. He will be towing a 35ft motor home. Before he starts off. We want to change his Front trans axle and rear diff fluids.
Would the fluids be
- front=80w-90
- rear=75w-140 or 75w-90.

 

No front transaxle on this truck...It has a front and rear differential.

This should not need to be changed this soon. Just check it and if the level is full (to the plug when you open it) then I would not touch it.

Only time I would touch it is with alot of miles or if you submerged it in water.

 

They shouldn't need changing yet , the rear diff comes factory filled with synthetic. Not sure about the front.
jr

 

Well we are not sure how the truck was driven. All we know is that he did have a 5th wheel hookup. But not able to confirm if the front or rear diff where submerged.

 

I would probably change them for piece of mind.......