There could be two solutions the first one is easy. Do you double clutch going in to low range? If you do not then by double clutching this will fix your problem. When I first got my 130 I used to just slide it in to low the same as I did with any other truck and hay presto it works for ages but as soon as I got to a hill going down out she pops engaging what I called the holy fu*^ing sh$# gear (hang on for dear life and push the brakes in real slow). It was not till I spoke up and asked a question that I got laughed at it (double clutching) is aparently in the manual, I still haven't got around to reading it probalily some really interesting things in there. All that aside if you do douple clutch going into low range then the problem is most likely the syncros being worn so yes open the check book or swipe the visa because int's in the box and that always will cost.