Differential lube

[tmcalavy]

Oops. Was crawling around under the truck today...found a tag on the diff that says use limited slip lubricant only. Didn't do this when I checked it and topped it off a few months ago...it's a Dana 60 4.10 near as I can tell. Never knew there was a different lube for limited slip rear ends, so what's the difference? When I serviced it I topped it off with 80W90 hypoid that I had in the garage. Maybe this is why it hums a little between 45 and 60 mph at highway speed? Not enough to be alarming, but I do notice it. Are these puppies hard to service if I decide to pull the pumpkin cover, drain and refill? The front seal leaks a little, but not much.

[fordman]

i'm guessing here. but it is probably similar to transmission fluid. since it would have clutches in the rear end.

[forrestbump]

Try adding a 4 ounce container of Ford's Friction Emulsifier. Since you only 'topped off' your 60, I doubt you've wounded your clutch pack. Here is an exploded view of what's involved http://www.partsmike.com/tech-help/d60-exploded/ this example is of a front axle Dana 60 and it's to give you an idea only as it was the first one I could find on the net to help you.

[Whateverman]

from what i've seen most of the gear lubes available these days have friction modifiers in it already so you won't have hurt anything ,but throwing in a bit of limited slip additive would be a good idea

[tmcalavy]

Got lucky and found some limited-slip additive at Autozone today...$5 for about 7 oz. Put it in the Dana 60 this afternoon. We'll see if it makes a difference with the mild road noise/hum.