Outer Limits 4x4 Board

low range keeps poping out but not under power only when going down hills and when i take my foot off the gas ive alse replaced the rubber bush under the stick but the problem hasent gone away its a 2.8l diesel and any help would be great

Sounds like the detent ball spring (holds the shift rod in position) has broken or lost it's tension. You can get at them buy undoing the 6mm allen key bolt out of the top passanger side of the case which is the high and low shift rod spring and detent ball plug, Once the plug is removed using a magnet get the spring and ball out then clean and refit the ball and new spring then do up the allen key bolt and that should have you on your way.
Some pic's to point you in the right direction

thanks for that ill give it a go