[laxman21]

That's a k1500 93 p/u.


Never seen a 88 up with the lock on the shifter.


I did find this.

Starting in about 1987, the New Process 231/241 series transfer case became standard in Jeep, Dodge, and Chevrolet applications. These transfer cases are part time 4WD (Shift positions 4HI - 2HI - N - 4L). They have a relatively thin aluminum housing. They are 1:1 direct drive in high range, and use planetary reduction gears for low range with a ratio of 2.72:1 They use chain drive for the front output. The NP241 was typically used in V8 applications.