Outer Limits 4x4 Board

Bought 3.2 diesel auto NP 2003 Pajero. Last year whilst still under warranty (just) injector pump failed. Whilst holidaying selected 4wd LR as per the manual which states select netural on automatic selector, place stubby stick into LR, shift big stick (auto selector into drive or 1st gear) wait 8 seconds automatic will then be told by LR sensors that low range is selcted. Lights on dash light up to tell you it's all happening. Push right foot down on go pedal and wait for loud bang like it's jumped out of gear. Went to Mitsubishi dealer & showed mechanic the procedure used to select low range all correct. No noise & gears were selected car performed very well. Out driving on tracks very muddy selected LR same proceedure, guess what, loud bang no gear selected just free reving. Went through proceedure again gear selected everything worked. Vehicle to Mitsy dealer again no fault found. Contacted 4X4 AUST Magfor advice & encouraged me to contact engineer in Sydney who has experience with this problem apparently one of the sensors is not doing it's job in the transfer box dept. Recently ran out of diesel no warning light. fault sender unit stuffed up. I thought it was fuel pump again because fuel gauge showed half way between empty & a quarter of a tank Vehicle not under warranty $168 dollars to owner. Contacted Mitsubishi who basically state they will consider assistance if service manager submits claim on my behalf. Vehicle is 3.7 years old. What's next? Hope it doesn't jump out of LR when transgressing the Victoria High Country mountains!!!