What type of differential fluid?

[seasonscape]

Calling Wyldman (or anyone else)!!! I don't think I've asked you questions before but was upset to see you go, just in case I needed your help. Glad to see you and everyone else around.

I have a ’97 Ford F250 Heavy Duty with IFS (pretty sure it’s a Dana 50). I want to change the front differential fluid but can’t get a straight answer from anyone what type to use. The manual says “4x4 gear oil”, Napa couldn’t help me out and when I called the dealership they said to use 80W90 without asking me any questions about the vehicle, so I’m a little hesitant to believe them. What is the correct fluid?

-Tim

[D&T Repair]

I use 80W90 in both the front and rear differentials....always have.

[paulsoccodato]

80w90

[wyldman]

Sorry I couldn't reply earlier,as the old threads were locked.

80W90 is correct.For the diffs,I'd go synthetic though,as they take a pounding on a plow truck,and it's something you don't change often.

[RPM]

If it has limited-slip diffs. you are supposed to put the friction modifier in too.

[YAKO]

id use 75-140 amsoil or mobil one.

[seasonscape]

Yep...I guess I should've posted this BEFORE I did the rear. Put 80W90 in the rear and was waiting to find out what to put in the front. What would you guys do? Drain the rear again and put synthetic in the front and rear or just put synthetic in the front? BTW, the truck just reached 100K.

-Tim

[Big Nate's Plowing]

I would go with amsoil or Lucas, lucas is better IMO either weight will work, as long as it is not a limited slip.

[wyldman]

If the rear is done,leave it for now and change it over to synthetic next year.No sense in wasting the gear oil.

[accutrax]

Just did my twin D60's with Amsoil synthetic 75w90. Not the cheapest stuff around but gear lube's cheaper than axle repairs. Good luck