GM Full-Size Trucks 1970-1979 Repair Guide



There are two transfer cases used on these vehicles. The New Process 205 is used in part time systems with all transmissions through 1975, and with manual transmissions only on 1976-79 vehicles. It has a large New Process emblem on the back of the case. The full time new Process 203 is used with all transmissions in 1974 and early 1975, and only with automatics from mid-1975, to 1979. It can be identified by the H-LOC and L-LOC positions on the shifter. All 1 ton trucks use model 205.

Models with the new process 203 full time 4-wheel drive transfer case, especially with manual transmissions, may give a front wheel chatter or vibration on sharp turns. This is a normal characteristic of this drivetrain combination. If it occurs shortly after shifting out of a LOC position, the transfer case is probably still locked up. This should correct itself after about a mile of driving, or can be alleviated by backing up for a short distance.