main differences between 73-79, 81-87

[GonicGM]

Originally Posted by cliffsta

On 4WD models, automatic front locking hubs hat worked at speeds up to 20 mph were available.

All GM 4x4's were produced from the factory with transfer case syncronizers and Automatic hubs and GM's promotion was "shift on the fly" as follows:

81-84 K1/K2
82-84 K3

In 1985/1986 either manual or automatic hubs were available. Automatics were available on K/V 1,2 through 1991. K30 could not get automatics after 1986.