I have 99 2500 5.9 Deisel with. NV4500. Recently started to notice a grind going to 3rd and 4th. At a stop takes 5-10 seconds before able to get into 1st 2nd and reverse at a stop. Never can down shift into 2nd while moving. Just replaced the master and slave assembly as I noticed a leak from the master. Still grinds. Got a valair hydraulic assembly and adjusted the rod all the way out. Same story. Before I begin driving the whole trans seems flawless and nothing difficult to get into. A while back added synchromesh and didn’t have problems driving when I did that. If I jack up the rear wheels I can drive through the gears without an Issue no grinding. Floating gears I get no grind whatsoever. Feels to me like the clutch isn’t fully working properly? Help would be appreciated!

 

How many miles on the clutch? It does sound like it isn't releasing completely.... but, I would think what you have done with the hydraulics *should* eliminate that possibility.... Unless the fork itself is bending....

 

No clue on the mileage on the clutch as I bought it from a guy who barely used it and put no miles on it. Truck has 220,000 miles on it. In addition to what I said earlier if I double clutch I seem to have no issue with grinding at all even if I shift very quickly while double clutching. I also can shift into 5 quicky with no grind at all and down shifting from 5-4 is smooth as butter.

 

Worn sychros? Though, first gear isn't synchronized..... neither is reverse.