popping out of 4 wheel drive

[83stepside]

hello all...i have a 83 4x4 step side with a NP208C trans-case.bolted up to a TH350 with a 4 inch lift.problem is 4x4 pops out intermintently with no pattern to it..sometimes i can drive 5 miles or so..no problem..then other times it go's maybe 1/8 of a mile then"thug" the whole vehicle go's into neutral (all "drive" is suspended) and the gears in the t-case start whining up like a jet engine..till i come to a complete stop..wait for the gears to whine down..then i can RE-enegage the t-case BACK into 4x4(lever movement of course required) BUT 4x4 lever does not move when 4x4 pops out..linkage seems to be good....any ideas of a "known" problem with this type of t-case??? I don't think its my hubs because the whole vehicle would not go into "neutral" if the hubs we'er bad...i just wouldn't have 4x4..but the driveshaft would spin..and i would be "in-gear"..correct???


thanks for your time

Brent rndsout@comcast.net