Alright, so I'm a little confused after reading another post.
My 1984 Sierra has what I thought was automatic locking hubs (no getting out of the truck to lock them by hand). There is a lever on the inside of the cab for 4hi, 4low, N, and 2wd. But after reading another post it seems like this is referred to as full time 4wd? Or am I reading it wrong? Or are the two terms interchangable?