NV4500 Mystery Noise
 

Hello!
Wondering if anyone has heard of this before. I have used a chevy NV with a dodge input shaft (read my sig)
First,
The noise sounds like a bad bearing and is very prominent in fifth at 60+mph with a noticable vibration. It is definately caused by backlash/thrust like when you are just at the point of accel/decel. It shifts fine but also has a slight rattle that comes and goes when warmed up and in neutral idling. The clutch is a new South Bend and a new throwout/pilot. Also the Gear Vendor is currently off the truck and out of the equation.

Second,
I had bought a used NV for the build hoping for the best but it made the noise right out of the gate. I didnt have time to tear into it so I bought a rebuild from a local rebuilder. I told him what it was for and needed a chevy NV with a dodge input, he said no problem. I now have the same noise in the rebuilt NV. He said it must be coming from somewhere else. Everything else checks out whithin the drivetrain. The noise is definately in the tranny. Just wondering if it might have something to do with the input shaft change that the rebuilder might not know about.

Third,
I found some time to take apart the old NV I originally had. I found that the rear mainshaft bearing was a loose fit on the shaft and the race was spinning in the case. Also found the rear countershaft bearing was doing the same. Used some bearing retainer on both, reset the endplay to .002 and back in it went. Didnt fix it, I have the same noise. The only thing left could be the countershaft front bearing race spinning as well or something with the input shaft, but everthing looked fine when apart with nothing noticibly wrong that could be making that much noise.

So what do you think?:humm:

There is a common problem with the 5th gear "anchor nut" comming loose on the shaft.

The dodge nv 4500's are more prone to the problem and there is an update kit with changed parts to tackle the problem but itr is not completely solved the last time I read about it.

https://www.dieselbombers.com/12-val...nsmission.html

Permatex grey large gap bearing retainer is the fix for that. Use it on the splines of the shaft and Permatex green snug fit bearing retainer on the nut threads. Guaranteed to never come off again.

Solid flywheel or dual mass?

solid

How does it sound in 4th gear? My first guess would be a bad bearing between the input shaft and main shaft.

I have noticed a similar noise in fourth as well but not near as loud as fifth going 65+. There is also quite a bit of rattling going on when coasting to a stop in neutral.