Hi.

2006 Dakota Quad Cab 4x2 v6

I'm changing the rear diff fluid and someone said I need a friction additive on top of the 75/140 Mobile 1 fluid.

Thoughts?

 

I believe if you have a rear locker, you need an additive. If you don't have a rear locker, then you don't need the additive. Just check the owners manual, if will give you the info you need.

 

The additive is needed if your truck is equipped with a limited-slip rear diff.

 

You need the additive if you have the limited-slip differential like Altair said. Before you head to the dealership and dish out about $7.50/ bottle, I have 2 bottles that I'm trying to get rid of. I used to have a Jeep Rubicon and it had a locking front and rear diff., but I ended up trading it before I changed out the fluids. My new truck doesn't have the limited-slip, so I don't need them anymore. I'd like to get $10 for both, and I can ship them to you if ya want.

 

If you read the specs of the mobil 75/140 you will see that it has a friction modifier built into the fluid therefore mobil doesn't even offer a friction modifier separately.