FRONT diff fluid wth?!?!

[oscrfsh]

i have to add to my FRONT diff fluid in my 99 ex 4.0 ohv awd....i emailed ford and they said to use ford part number f1tz-19580-a and the ford specification is wsl-m2c191-a...i dont have a clue what that means, i tried to google it..its seems like it came up a 75-140 weight with maybe an friction additive to it?? i dunno, i went to the dealer and the guy sold me 80-90 weight...what should i do??

 

[2TimingTom]

I thought it was listed in the owner's manual.

 

[obie]

If you have a 4.0 you don't have AWD. Do you have 4WD? And you shouldn't need friction modifier in the front diff. With my 5.0 AWD its 3.5 pints of 80W90 gear oil. That's the standard for a Dana 35 IFS axle.

 

[IZwack]

Go with what the dealer said and no friction modifier is not needed since the front never came with a Limited Slip differential. Be aware that adding fluid to the front is not a straight differential fluid fill as suspension/frame parts are in the way - so typically you'll need to crank the steering wheel one way and then use a long clear hose to extend your reach.

 

[oscrfsh]

i have a siphon pump to put in fluid, i had to get one for the transfer case so getting the fluid in shouldnt be to hard. I do have the awd and a 4.0 , there is a switch on my dash that says awd 4hi or 4 lothose are the only three positions of the switch and i always leave it in awd position.

 

[oscrfsh]

o and i bought id used so unfortunately no user manual, so since the dealer gave me the 80-90 i should just use that then?... its got to be better then running it with nothing..i stuck my pinky in there as far as i could and she came out without a drop on her

 

[oscrfsh]

my apologies, the switch says..auto..4wd and 4 lo those r the three positions...so i thought auto was awd..no?

 

[obie]

That's auto 4WD, not AWD. Auto 4WD kicks in when the computer senses wheel slip, and engages 4Hi. It's also a 50/50 torque split front to rear. AWD is full time and never disengages and uses a different transfer case. It's also a 35/65 torque split front to rear. And yes, you should use 80W90. Also, if its been run for a while with that low of fluid, you may need a diff rebuild. Before you fill it though, check your diff seal, pinion seal, and cv seals for fluid leaks.

 

[oscrfsh]

so what are the advantages and disadvanteges between awd and the auto 4wd?