Other than it takes synthetic SAE 75W90, I can't find any information on the rear axle. I think mine is a bit low...I can just barely touch it with my little finger, does anybody know how much should be in there? Also, the manual says to change the front axle at 50k, same for the rear?

Thanks.

Check this thread. (http://www.dieselplace.com/forum/showthread.php?t=33348)

I filled mine up to the bottom of the hole, cant hurt it to change it, I put mobil 1 sythetic in mine.

I changed both the front and rear to Mobil 1 syn at 12K. Mine was low as well.

All these trucks come with the fluid level about 1/2 to 3/4 inch below the fill hole. Manual says this is proper level. Old school says fill to level of hole. I'm old school so filled mine up.

GM says 3 qts, but that left it short. Can't reach it with my pinky, but my Pinky is short LOL. Guess I will have to buy another qt of grape juice and top it off. Why can't they just say it takes 3.5 qts and get the job done right the first time?

I had a long discussion with two Chevy diesel mechanics today. Change it at 50k. The capacity is 2.8 to just less than 4 quarts (depending on who you listen to) and the quantity can be as low as .8" below the hole to just below the hole.

I believe the owners manual says 4 quarts for the stock differential cover. I changed mine and it only had 2 quarts in it. I put in Mobil 1 with almost 4 quarts.

1/2 to 3/4th of a inch below the fill hole is correct...

Mobil 1 syn 75w90 in both diffs... 4 rear/2 front