Draining and changing the gear oil, front and rear, in my '01 F-250.

Chilton's says to use synthetic gear oil.

Wal-Mart sells a synthetic BLEND, correct viscosity, cheap.

Is this stuff okay to use?

 

i could be wrong but... i think wal-mart oil is quaker state. i have a 01 250 as well. how many miles on yours??

 

NO, FORD specifies only FULLY synthetic gear oil/fluid. 75W-140 for the back, 75W-90 for the front.

 

unless your doing alot of towing etc... you should never really have to change it right?? eventually your axle seals will leak but..until that happens.

 

You must use full synthetic 75W140 in the rear. You may use any 75W90 or 80W90 GL5 spec in the front. Change is recommended every 100k.

 

my two cents $5 at walmart for oil and 1000 for diff repair at ford or $10 for oil at ford. I would go for the more expensive ford oil i tried quaker state and my limited slip made noise in the corners went back to ford all good

 

If you have a limited slip, you have to add Ford friction modifier if the stuff you use doesn't already have it. Motorcraft 75W140 does not. I *think* Royal Purple and Lucas does.

 

After doing the research on here, I used Lucas oil for the diff's. I guess I would rather spend a few extra dollars now, than costly repairs later.


...my 2 pesos

 

Mobil 1 already contains the LS fluid/friction modifier in it. Upon putting it in my rear diff, i have had no problems or sounds from the LS unit. Putting too much friction modifier in is not a good thing, either. 4oz is what is recommended for the rear LSD, if your fluid does not contain it.

 

Mobil 1, Red Line, Royal Purple, and Lucas all have the friction modifier and meets or exceeds Ford Specs. They all work well. It's more brand preference and pricing at this point. Now is also a good opportunity to install Mag Hytec differential covers.