Is there a drain for the rear differential or do you have to pull the cover? Also is anyone using synthetics? If so what type? How about the front?

i don't think you have a drain. the 3/4 tons have one but i think you have a 1/2 ton diff. check anyways. i believe your diff came from the factory filled with synthetic front& rear. your front diff has a drain. i wouldn't get the gm synthetic gear oil because it costs about $15 per quart. your owners manual should tell you what to put in.

I think there is a plug underneath the differential. You will need the 1/2 socket square end to get it. It is directly underneath towards the front. The fill is on the passenger side. As for synthetics, I think that is what is required!