Ok first of all this is not my truck. The truck belongs to my brother but he doesn't know anything about working on it. I am currently at Wyotech for diesel technology so I have some experience with larger transmissions. Anyways I recently installed a southbound dual disc 3250 clutch in his 01 24v cummins. The stock clutch had been slipping in the higher boost levels, so it was time for a better clutch. He also had a complaint that it made a noise when shifting gears, so I drove it one weekend while home and figured it was a throwout bearing cause thats what it sounded like. After installing a new clutch it made the same noise. I should have checked the input shaft clearances more thoroughly when I had the tranny out but I didn't think of it. I am thinking it is the input shaft bearing which I found out is a pain in the nv5600 cause you have to disassemble the whole tranny. Is there any way to confirm this is the cause? Also how difficult is this job? I am not afraid of a good challenge but i don't want to go into a job blind tho either. any help is appreciated

 

From my experience with new venture the forward thrust bearings are plastic and if they ever get hot they cause a clearance issue as you can imagine. this causes the front bearing to unload and become loose ultimately failing from friction over heating. low fluid in the gear box is the biggest cause IMO.
If you want to check the input shaft bearing you will pull trans and remove the throwout bearing slider shaft you will then be able to dial indicate the axial < > play on the shaft. Or just feel for excessive play in and out and check for a cooked smell (you know the one).

 

Well I feel rather dumb now. I drove the truck for a week and crawled under it. The rear universal joint is going out and making the noise.

 

Wow you must be livin right wish I had your luck rock on man.