You said you didn't know if yours is not working? Was it working before? You have the correct fluid? IIRC, no friction modifiers on the G80? You need to remove your differential cover and see what the internals look like. Are you on stock tires? What's the use for the truck? Light off-road?
I don't know of anyone modifying their G80, unless you are asking about fixing it up. If it's only the governor that broke and everything else is okay, that seems like an easy fix.
Why is the Tru-trac not a good idea for off-road use? I hear they are great all-around. I couldn't remember if that's what
@kennythewelder had installed in his truck. I believe the only downside is you have to "fool" it by tapping on the brakes if one of the rear wheels come off the ground and get it to engage? I wouldn't really think that's a downside myself, just learn to operate it. Big advantage is no air lines, compressors, electrical and other stuff to worry about.
I don't know much of else out there for the GM 9.5" maybe ARB air locker? Lot's of offerings for the 10.5" though:
A 14 bolt rear axle is one of the simplest and cheapest strength upgrades you can do when you need a strong rear end. Because they're cheap and strong, some of the options are a little different than other axles, and usually those options are also more budget-friendly. This is the best source...
www.roundforge.com