I believe read somewhere that someone had used the same fluid for the automatic trans in their transfer case (can't find it now). This seems questionable to me, however, I do have some extra Castrol Multi-Vehicle ATF leftover. Can the transfer case be filled with this, or should I only use the 75/140 synthetic gear oil I have seen recommended? Thanks!

 

Is it April Fool's Day?

 

PUtting ATF in your transfer case will only last you for a very short period of time until you end up destroying the transfer case. The use of the synthetic 75W140 gear lube is a must. The big reason is that the full synthetic fluid has a high resistance to crushing under heavy loads. What does this really mean. The gear lube will maintain a certain amount of lube between the gears when you are accelerating due to the thickness of the fluid. Where the ATF fluid is going to be crushed and squirted out the sides, allowing for metal on metal contact. This is going to result in a very short life span of the transfer case.