Changing rear diff fluid...no friction mod needed with Mobil 1??

[Mustang5L5]

I just finished replacing a leaking axle seal and am about to fill the rear end back up.


Since it's sunday, i can't get friction mod from Ford

However, i bought 2 quarts of Mobil 1 synthetic ($16 each) and it states that it already has the additive included.

So i can safely add it and not worry about the ford friction mod correct?

Just wanted to make sure before i started driving around.

I'm gonna go return the tools i needed for the axle seal and look for a pump and then tackle the fill

 

[03ghoststang]

if it says that it has modifier included then your good to go........thats why i use royal purple already comes with it

 

[Scorcher2005]

Where did you find the Mobil 1? I look everywhere and cant find syn gear oil.

 

[Mustang5L5]

Autozone has it.

 

[Mustang5L5]

So i filled up my diff. I had the car on ramps so i went to the fill hole instead of slighly below it.

Should i go back and top it off after a few days? Won't the fluid flow into the axle tubes and the level slightly drop? Something i should be concerned with or not?

I only got about 1.5 quarts in before it came out of the hole.

 

[Nightstick]

I got Mobil 1 75W140 diff. fluid at Advance autoparts.

No extra modifier needed.

It should hold about 2 1/2 quarts if you took the diff cover off.

 

[blackfang]

When I installed my girdle I went with Mobil 1 being napa was out of Royal Purple(which is whats in the trans and engine).

 

[SVT32VDOHC]

Last time I changed diff fluid I swear it took just under 3 quarts. I got two full bottles in there and then the 3 one it started leaking out. Over filling it is just as bad as under filling it.

 

[Bad92GT]

i put friction modifier in it with it.. is that bad 0.o

 

[Tally_4.6]

If you weren't on level ground when you filled it, it will be low when its back on level ground.

 

[larrendeuce]

I was talking to a friend who was a ford tech. I asked him about the gear oil service interval since the owners manual says the axle is lubricated for life. He said its filled with ford synthetic gear lube and its like $30 a quart, and its much better then store bought lubes. 3 qts and 4 oz friction modifier.

 

[BennyBlown2v]

Proper fill spec per ford service manual:

1.66-1.77-liters (3.5-3.75-pints)
6.4-14.3-mm (1/4-9/16-in) below the bottom of the fill hole

I ran the mobil 1 synth with no added friction modifier on my built solid axle, and my stock setup - it worked GREAT!

 

[BannonJr]

I gotz 2 bottles of RP in mine...but looking at the post above...looks like I bettah top it up...eh.

 

[Mustang5L5]

I gotz 2 bottles of RP in mine...but looking at the post above...looks like I bettah top it up...eh.

1.77 liters is 1.87 quarts...so just under 2 bottles

 

[R.J.]

Yes the haynes manual also says 3.75 pints or just under two Qts. If you only got 1.5 Qts in then you are a little low.

 

[steve_stang2003]

I just finished replacing a leaking axle seal and am about to fill the rear end back up.


Since it's sunday, i can't get friction mod from Ford

However, i bought 2 quarts of Mobil 1 synthetic ($16 each) and it states that it already has the additive included.

So i can safely add it and not worry about the ford friction mod correct?

Just wanted to make sure before i started driving around.

I'm gonna go return the tools i needed for the axle seal and look for a pump and then tackle the fill

I used Mobil 1 as well and if I recall it said something like "For Severe Applications additional friction modifier might be needed"

Check the fine print on the bottle.

I added a bottle of the Ford stuff anyway.

 

[Mustang5L5]

Yes the haynes manual also says 3.75 pints or just under two Qts. If you only got 1.5 Qts in then you are a little low.

Yeah, i'm going to go back under this weekend and top it off.