If it is the rear one, Then you have to remove the rear end plate to drain it.
The front has a drain plug just above the skid plate, on the right bottom side. and a fill plug above the drain plug.
5
The front differential uses 80w90.
To change the differential oil on a 2010 Yukon XL 4x4, start by safely lifting the vehicle and securing it on jack stands. Remove the differential cover bolts and carefully pry off the cover to drain the old oil into a pan. Clean the mating surfaces, replace the gasket, and then refill the differential through the fill hole with the appropriate gear oil, ensuring it reaches the correct level. Finally, replace the cover and torque the bolts to the manufacturer's specifications.
Unless you have a 4x4 or 6x6 unit, there is no front differential.
85W90 gear oil.
80-90 PL-5 gear oil
How do you change the oil filter sending unit of a 1999 suburban?
SAE 75W90 synthetic gear oil
Hypoid gear oil 80w90
Yes, differential fluid breaks down and becomes contaminated over time. sometimes changing the differential oil causes the axle seals to leak because the new oil will be thinner than the old stuff so keep an eye on them.
It is GL-5 and the weight is 80/90 gear oil.
5 qts with a new filter.