I know this isn't a transmission forum and it's not exactly dentside specific but the transmission is in my dentside and I didn't get a lot of replies from my thread in the general auto forum so here go's.
Hi guys I was hoping someone could help me with a noisily transmission of mine. I have 1979 f250 crew cab with a nv4500 trans put in by a previous owner. So I don't know anything about the trans, clutch, or driveshaft or what condition they are in.

The transmission makes noise. A lot of it. Mainly in 4th and 5th gear under acceleration. If I'm rolling and let off the throttle or push in the clutch it goes away. The only way I can describe the sound is it sounds like you pulled out of some mud and are accelerating down the road, and the tires are throwing mud onto the body. It sounds a lot like that.
It gets louder if I put my ear to the shifter while it's doing it. 60-65 in 5th is a different, more rattly noise. It gets louder the faster I go. It's especially loud when it's cold outside, it's also slightly more difficult to shift. As if it doesn't want to get into gear. I've kinda chalked that up to oil being cold and needing warmed up, but my drive to work is only 12 miles and it never really gets any better in cold weather. The top of the transmission will get a little warm but not much else. If it's warm outside that problem goes away, but it still makes a lot of noise.

The clutch used to make a very slight wurring sound but I can't here that anymore. Occasionly upon accelerating from a stop and releasing the clutch the truck will suddenly lurch , like I let out of the clutch to fast or gave it to much throttle. It only happens occasionally (more frequent of the truck hasn't been driven in a couple days it seems like) but I can't tell if it's a tuning issue or something with the clutch. The truck runs fine and it usually only occurs around a certain spot on clutch.
Like I said I wasn't the one who did the swap so I have no idea how many miles are on the transmission or clutch. Can anyone take a guess at what the problem could be?

The truck doesn't have ANY sound deadener, and there is a 4x8" hole where the old trans cover used to be which is covered up with carpet. So it may be a little louder in the first place. Any help would be greatly appreciated.

 

I have a nv4500hd and its dead silent. Sounds like you may have a bearing issue, but have you checked or changed the fluid lately?

 

Sounds like you have two issues, the last nv4500 made the mud/tire noise in 2nd and 3rd cause the throw out bearing was going out, the other noise in 5th is your gear separating, what happens is a brass bolt that's rounded off on the end counter sinks in and holds the gear onto the shaft to keep it from traveling forward or backward over time the brass bolt gives away. Had this trouble 4 times in 6 months when I was hotshotting with a Cummins that had a nv4500. Good luck bud

 

Have you ruled out U-joints and the 2-piece drive shaft being in phase ? Or possibly the custom work that had to be done to the drive shaft length to fit being out of balance ?

 

I don't think it's the driveshaft because these problems just started and the clutch does make a noise when depressed which is indicative of a throw out bearing right?

The way I understand it is the 5th gear nut is a simple fix of just welding the nut in place correct?

The fluid was replaced a couple months ago. I made sure to use the recommended fluid and filled it with the recommended amount. I don't remember the exact brand it I might be able to find out. The old fluid was black and flowed like syrup.

Since this is a Chevy trans bolted to a Ford how would I go about buying parts like clutches and throw out bearings for this?
If I did the work myself how much would this cost me? I'd look it up myself but I don't know which parts would be used.