newbie: 1996 12v with 500,000 on the clock
 

i bought a stock 1996 2x4 2500 with a nv4500 tranny the owner before me had the 5th gear nut welded @ 427,000 it now has 495,710 on the clock and its making a grinding sound when it is put in 5th gear any responce will be helpful

welcome to diesel bombers cain could be a broken tooth ,bad synchros, bad bearing, any of the above especially with that many miles heres something for you to checkout and read and a few links to order parts if thats what you want and good luck keep us informed of how its going and again welcome :yeah: https://www.dieselbombers.com/12-val...questions.html

My buddy just replaced his trans for $1050 exchanged. It had the updated mainshaft and a cast iron output shaft housing.
4X4

I would say synchros, but 3rd gear is usually the first one to go out. Has the trans ever been rebuilt or replaced? Most of the time a NV4500 only lasts about 250000 or so before its bearing and syncho time. Some last longer but low oil or a non-GL-4 oil is really REALLY hard on them.:c: