t- case problems

[83chev4x4]

i have a 83 chevy k10 auto with a np208 t-case. when i am in four wheel it likes to jump out to the last gear it was in. when i go from 2 hi to 4 hi after a while it jumps back into 2 hi, when i go from n to 4 hi or 4 lo it jumps into n. it really ticks me off when i am four wheeling because i always thing the tranny whent. any ideas would be apreciated TJ

[JK5]

How is the shifter, does it seem sloppy? Sometimes a sloppy shifter (especially off road) will shift out of 4H!!  

[83chev4x4]

shifter is tight. it does it when ever it feels like it (not just when im on the gan or off the gas). thanks TJ