I have a 76 K10 and it has the np203 t-case. It came with a full time transfercase, but the previous owner has put warn part-time hubs on it. The wierd thing is the truck has to be in 4lock in order drive. In 2hi it just spins the front driveshaft. I have had no problems with it but it concerns me that there is an excess amount of wear going on, because the front driveshaft is spinning with the rear but just unlocked at the hubs. Where can i find the part-time kit that goes into the t-case, and untill I do that, am i better off with the hubs locked and in 2hi, or the way i've been driving with hubs unlocked and in 4lock?