Just a quick question about how much oil is in the rear diff., I think mine is a Dana 70 with the anti-spin option. I was a the dealer today to pick up supplies and they were not sure the refill spec. until they looked at the computer. They told me it was about 3.6 litres and they said one bottle of additive which was 4 ounces ( 120 mil) was enough. The thing is my owners manual says to use 6.5% additive of refill cap. That would be almost 8 ounces or 234 mil. So has anyone done a refill and how much should I use. The dealer said a bit too much wouldn't hurt but not enough would cause a shutter and binding. The reason for the fluid change is the cover gasket is leaking, I found a TSB on that problem. I guess the fluid reacts with the RTV sealant and it fails.

 

i changed mine to royal purple, no friction modifier required

 

I believe the dana 70 takes 7 quart, If you use one of the higher end synthetic brands of oil, ie amsoil royal purple ect, i dont think you need to use any friction modifier, if you do and some, it wont hurt.

 

On my Dana 80 i used 8 onces of friction modifier and a full synthetic gear oil.

 

Where do you get this friction modifier?

 

I got my additive at the Dodge store. It came in a 4 ounce bottle. I found out today that my rear axle holds almost 4 litres of diff oil with the 2-4 ounce bottles of additive. My owners manual calls for 6.5% additive as per fluid cap.

 

By Dodge store, you mean dealer, right?

 

Sorry my 5 year old calls the Dodge dealer the Dodge store, I guess I'm starting to talk like him. Anyway I guess you have to use the stuff or the clutches will chatter and things won't work right.