Repzard

Hello Mfers

I just changed out my pinion seal.Seem like it went well.
Followed the video I put in thread a few day back.
also replaced rear diff seal and fulid.

Well i decided to use Mobile 1 75-140 full syn LS gear oil.
Now the reason Im making this thread is there is a big confusion wether to use FM in this gear oil. Mobile states that this gear oil has FM in it but may also add some if needed.

Well my question is how many MFer use this gear oil in their 8.8 Trac Lok ?
Did you use Ford FM ?
If so ...How much did you add? Ford recommends 8 or 4 oz ?

Another thing I hear is that full syn gear oil doesnt need FM where it is slippery enough. Is this indeed true?

Very confusing situation I see some still use FM with full syn gear oils
Guess I need to do some figure 8 in a parking lot and see if there any chatter ?

Thanks MF


Repzard

uberstang1

The last time I did a fluid change I used this same fluid and just added 4 ounces of the autozone friction modifier. I figured better safe than sorry and it always spun both tires when making a patch so I'm pretty sure it was win.

BraMas

to be safe I would add some FM. I've had to add FM to RP before because the clutches would chatter and your also not supposed to need FM with RP

Unleashedbeast

I've tested two top tier true synthetic base stock gear oils (Amsoil and Royal Purple). I have heard claims that friction modifier wouldn't be required. First, I would not pour in any friction modifier. During testing, the limited slip clutches in the differential would make noises going around sharp corners (wheel turned to maximum in either direction).

Then I added 4 ounces of friction modifier, did the same figure 8 testing, and the noise was gone. Don't take the manufactures word for it. Add 2 ounces of FM with the gear oil, if it's silent, you have added enough. If it is still noisy, add the additional 2 ounces.