Gear Lube

[Dave Hickman]

Going to change the gear oil in the rearend. My choices are Mobil 1, Valvoline or Royal Purple. Price is the same. Any thoughts on which is better? Or are they the same?



Thanks,

Dave H.

 

[Rodger Tellefson]

I use Royal Purple in my engine, tranny and differential.

 

[Todd Z]

Honestly I used the RP and M1.. rp in my 03 and M1 in my 04..



The RP was way thinner and easier to push into the diff....



Todd Z

 

[Alan Peters]

I used Valvaline Synpower in the rear. Don't forget the friction modifier, which you can pick up at any Ford dealer.

 

[Mitch Spiegel]

If you use Mobil1 or Royal purple gear oil do you need to add the friction modifier?

 

[Jack Wiley]

Mitch,



Yes use the friction modifier for the rear diff with Royal Purple, Mobil 1 or any synthetic lube. I use Red Line and they make a Ford spec friction modifier for the Trac-Lok

Limited Slip rear gears. I've used Red Line for 15 yrs and have been happy with its performance and it holds up well according to my UOA from Blackstone Labs.



John

 

[Mitch Spiegel]

Thanks, Do you a part number for the modifier? I saw some on ebay want to make sure I get the right one.

 

[Johnny O]

Any of those three will be fine. I use Mobil 1.