Bought an AWD 06 Escalade about a year ago. It's off warranty now and has developed a humming soundwhen you accelerate,most notable between 30 and 50 miles per hour. If you let off the accelerator, the hum stops.It's my wife's daily driver so I never noticed it until she told me about it. I immediately checked it out and discovered the front diff was practically empty of fluid and showed signs of a leak somewhere. I added about2 quartsof synthetic75-90gear lube, but the noise hasn't gone away. In fact, mywife says it is getting worse.

Anyone had to replace one of these diffs or had the ring and pinion replaced? I'm wondering what it's going to cost me. I'm debating whether or not to change the entire diffmyself but I'm not sure what rebuilt/salvage units would interchange. I think it's a 3.73, as I don't think the 06 had any options for gear ratios. Does it have to be a unit from an AWD SUV or do the 1/2 ton pickups run the same setup? I imagine any 02-06 unit would work, but knowing my luck I'm wrong. Anyone have any advice?

 

Being it got cooked due to lack of fluid, it may not be rebuildable. Sometimes bearings will seize on pinion gear and diff is trash. Escalade/Denali front diff. is a little unique due to AWD, however one from a auto 4wd 1/2 ton Z71 may work. It's not bad to change out, but you wont want to try it alone.