On my '85 Burb with a 700R4, NP208, and 10bolts, when I run it in 4HI on a hot day for extended periods of time (cruising soft sand on the beach), every once in a while it will just pop into neutral, both axles. And if I try to shift back to 2WD the shifter won't move, it will go into neutral but then it will make a terrible stripping noise. It just kind of will stick in neutral but in 4HI positiion. To shift back into 2WD I have to actually turn off the engine, then it will shift back into 2WD (or 4LO), and work fine until if pops into neutral. I'm thinking the t-case is fixing to go out. What do you guys think?