40 miles from home on vacation to Florida, the NV-4500 developed a second neutral, right where 5th gear used to be.A mechanic friend got us right in and did the whole job for $250.He used the Chrysler split nut and some synthetic lube he uses in the NV-4500's.It is a little difficult to get out of 5th now when hot (towing) and didnt used to be. Fine when cooled down.We didnt have Royal Purple to put back; we have run RP for 110,000 miles with perfect shifting.5th gear was a little sloppy fitting on the shaft splines, 250,000 miles of wear I suppose.Any thoughts on the split nut fixing the problem of the nut backing off?And any thoughts on why now it is hard to get out of 5th gear when hot?TIA