hey guys,

Just picked up some Mobile 1, 75w-140 syn gear oil to do a rear end oil change this weeked.....The bottle states it works in both convential rear ends and in limited slip rear ends. Any thoughts regarding the need for an additional friction modifier?...

Thanks

 

click here and watch the videos in the first post, that is my thoughts on what oil with no modifiers that I put in my truck.....

also when i replaced the rear end oil for sells the rear end diff cover for an 08 super duty for just over 50 bucks, it is aluminum with fins to help cooling (if you dont think you need cooling tough your rear end after driving just 20 miles unloaded) you will need to get longer bolts (I got them from lowes)

 

Yep I already have the 08 diff cover, and am going to swap it out when changing the oil....

 

i say add the mobil one without any modifier and if your rear end starts to chatter add some modifier then.

 

I used Royal Purple that already had the modifier, but if I were in your position, I'd buy the modifier from Ford and if you didn't need it, then return it.

 

where do you get the 08 diff covers for such a good price?

 

Thanks for the info guys, I did just that...purchased the friction stuff, and was thinking of only using it if needed...just wanted a couple opinions...

I purchased my cover from FTEPartsGuy.....$55 shipped to my door.....

 

DieselManor - Ford Sterling Differential cover heres a pretty good deal from diesel manor.

 

With bolts:
DieselManor - Ford Sterling Differential cover

Without bolts:
Powerstrokeshop.com

 

The place I went to also used Mobile 1 75w-140. I got lost of chatter. The first bottle of Ford Friction Modifier lowered the chatter. The 2nd, removed it.

Be careful with the FM. It stinks.

Neil

 

Do yourself a favor and pull the VSS off the top of the pumpkin for two reasons.
1. Remove the metal fuzz from it so it can get a good signal from the ring.
2. It is way easier to pour the thick fluid into that hole on the top.

Good luck.

 

I used the mobile 1 and I haven't needed any friction modifier.

 

I used Valvoline Syn-Power and have no chatter.

 

Ok, brain tired, what is VSS?
And you are talking about filling the fluid from the top, not FM, correct?
I haven't changed mine yet so I assume I fill from the top.

 

VSS is Vehicle Speed Sensor on top of rear end. It apparently has a larger hole than the fill plug.

The FM and lube go in the same way.