Noob here...
Just picked up a leftover, new '04 2500HD Crew 4x4 LS w/ a 6.0L and 5 speed manual. Got a transmission question.

The truck is always buttery smooth between Low (1st) and 2nd gear, and from 4th to 5th. But... my 2-3 upshift and sometimes my 3-4 upshift are sometimes very clunky and noisy, and sometimes buttery smooth.

I've only got 400 miles on it, and I'm changing my driving style to smooth out the shifts without much luck. Is it just "pilot error"? Is this clunkyness common since this is a HD truck? Does it need to "break in" more if this isn't normal before I get worried? What is the stock fluid, dino? If so, has anyone replaced it with synthetic?

Also, what transmission is this?

I'm pretty sure the trans is an NV4500, made by New Venture Gear.

Sorry, I can't help with the notchy shifting, I've never driven one. The only standard's I've driven have had mucho miles on them.

Perhaps it's because the truck is still new. Get some mileage on it and see what happens. Maybe it's because it's been so friggin' cold lately also. I dunno if your location of Washington is DC or the state, but here in PA it's been basically stupid cold.

I say give it some time and see what happens. In a few thousand miles hopefully it will loosen up and be a real treat to drive. Otherwise, I'd take it to the dealer.

Good luck, have a good day!!

Dan