Rearend Oil

[duramax02]

I am wanting to replace the oil in the rearend on my 2500HD. Do I have to use the $27.00 a quart rearend oil my chevy dealer sells, or can I use Mobil 1 syn. 75w90 from autozone? What's everyone here using?

[silverado]

Duramax02
I've been using Mobil 1 syn 75w/90 for some time
now with no problems. I use it front & rear and I pull a 11500# 5ver.hope that helps.
Bruce

[chipper]

My dealers lead D/Max tech recommends 75-140 syn for the rear when pulling heavy loads.