ph_661

my diff fluid really needs to be changed. ive looked up online some instructions on how to do it and it doesnt seem that complicated but it looks like there are a lot of ways i can f* it up. i really have no mechanical experience. i change my oil, changed my shocks and thats all ive done to my truck.

would someone with no experience like me be capable of changing the diff fluid? have u done it and how hard was it? how much would it run me to get a mechanic to do it?

its a 98 f150 4.6 v8 automatic

Kattumaram

Unless you're determined to learn home-maintenance for your truck, leave changing the diff lube to a pro. Labor for the work should be less than one hour @ $65/hr and the lube should not exceed $20. Gasket material is a tube of black silicon sealer, about three bucks.

If a pro does the work, remind him that the refill lube should be 75W140 GL5 full synthetic only. Valvoline is a good brand.

bradford

I went to NAPA and bought the fluids for oil change ( synthetic ),
front and rear Differentials, trans. ( manual ) and transffer case.

they looked up types and capacities, and sold me 75-140 for the front
with a " Differential Friction Modifier "
he didn't reconize the lube for the rear so he sold me the same as for the front.

Thanks to some folks on another thread, here I know I have 3:55 gears W/O limited slip
Do I need the friction modifier?
will the 75-140 work in the rear differential ?
or should I return that and pay the dif. for synthetic ? ( they carry Valvoline, Amsiol and Royal purple)
97 4.2

Thanks, Brad

kev210

If they looked it up and gave you 75-140 then its prob something similar to the oem so it'll do the job.

If you dont have limited slip then you shouldnt need a friction modifier.

bradford

Tag on rear said 75-140 synthetic.
took non-synthetic back. older counter guy enlightened the guy that sold me the wrong stuff.
every thing changed out.
next time I need somthing I'll check it out here first.
Great site, Good advice. Thanks Brad

sundog49

Will 85 140 synthetic work in place of 75 140? 2000 F-150 355 limited slip. How much friction additive should be added?