My 99 silverado seems to be dragging the drivers side rear wheel when I turn. I checked and changed the fluid. Not sure what's up. Am I out an axle seal or a rear end or something else? Where do I start? any insight?

 

Check your RPO codes in the glove box to see if you have a locking differential
might also want to pull the rear drums off to make sure its not a brake related issue...
for what its worth you might try backing up when it locks up to see if is the locker...I had a 97 Tahoe with a rear locker and a couple of times for what ever reason it would lock and not dis-engage and backing would release it....