I am purchasing all the stuff to complete the rar end change to 4.10, and the last thing to get is the oil. I have been checking around for the different 75W140 Synthetic gear oils, and where I am the choices are very limited. I'm in Canada, and good ole Canadian Tire only stocks I think a Valvoline (sp?) synth gear oil in 75W140.

Since I am close to the USA border, I went over to Michigan to see what I can find, and at Autozone they have Mobil-1 synthetic 75W140.

Is Mobil-1 good for the gear oil? If so, do I still need to add the friction modifier to it, as I have seen that it has it in it already.

I have tried to source out Royal Purple, but I don't want to look at getting it shipped, as the costs would be too much.

 

I used Mobil-1 synthetic 75W140 (it's expensive!).

And yes to adding Ford friction modifier.

 

Redline synthetic. It's less expensive than Mobil 1 or Motorcraft and works very well for Ford applications.

 

Thanks Bill.

I know it's expensive. In Michigan it's $15.99 a bottle. I guess I will just pick them up the next time I am over there this week.

Now just have to get the gears installed!

 

I would consider mobil-1 and royal purple to be equivalent to each other

 

Just don't use Mobil 1 75W-90, it has been known to be ****-thin and allows for premature axle bearing failure. I've never heard of this problem with competing 75W-90 synthetics, so I am avoiding all Mobil 1 gear oils.

It's interesting how Mobil 1 and Motorcraft synthetic gear oils can cost nearly $20 per quart, while other true synthetics such as Red Line, Amsoil, and Royal Purple are under $10/quart and have generally seen limited distribution.

 

I used RP 75W140 whichc already has friction modifier added.

 

Amsoil

 

For rear gear oil, I've always been happy with Royal Purple, Amsoil, and Redline.

 

I have used Redline with excellent results. Any synthetic will be fine.

 

Yeah, most people seem to think that.


I haven't personally used any Redline products, but I know a lot of people who sware by them.

I think if you go with anything like Mobil 1, Royal Purple, or Redline (all with friction modifier), you'll be set.

 

+1 thats what I used also