I believe you're referring to the G80 locking rear differential? If you open the glove box, there will be a sticker listing all the option codes. If you see G80 ...

I believe you're referring to the G80 locking rear differential? If you open the glove box, there will be a sticker listing all the option codes. If you see "G80" listed, than it's the locking rear diff (most GM trucks have this). There have been reports of them exploding if you put oversize tires on; when they slam into the locked position, it puts a ton of force on the internals. Other than that, it's the best differential on the market today (at least from the factory).

I plow with my truck, and haven't had a lick of trouble with either the transmission or the differential.

G80s are the best. Most of the grenade stories come from the rock crawler crowd. So unless your doing something that extreme, your diffy should be fine. Just keep the fluid up to date.

What is the difference between the 2500 and the 2500HD?