<hr style="color:#ffffff; background-color:#ffffff" size="1"> I found the tag on my diff (doing an oil change now).

The tag said 605685-5, 3.55, and one of the gears had DANA writen on it so I'd guess DANA but I see a lot of suggestions that it's a Sterling. I'm so confused.

Also the door tag says Axle 39.

 

Well it's not a locking diff, so you can use any gear oil in it. Something like 75W-140 will do. Or 85W-90.

 

sounds like a dana 60 with 3.55 gears, open diff. for further confirmation, i once stumbled upon a site that shows pictures of many diff covers with their axle identity listed with them.

all of our axles that aren't limited slip are ok on just about any gear oil

 

Here's something I bookmarked, about halfway down the page: Differential Identification | West Coast Differentials