what insde the transmission can make a racket? i have been hearing a noise and decided to crawl under the truck to look around and it sounds like the transmission,somewhere around the the bellhousing.

 

The most frequent sources of noise with these NV4500's are actually not the transmission, but either the throwout bearing or the pilot bearing.

Other than those, you get rear mainshaft carrier bearing failure, but usually not at such low mileage unless you have pushed or pulled quite a bit; misadjusted or worn shifting forks dragging; or the infamous fifth gear countershaft nut falls off and lets that shaft and gear slide back and forth.

Throwout bearing noise can generally be easily isolated as it only occurs when you press the clutch, and will change pitch depending on how far you have depressed the clutch pedal. The pilot bearing will squeal or click when the truck is in gear and the throwout bearing is depressed, and will only make noise when the truck is totally stopped and the clutch depressed in gear.

Rattling or growling when the rig is in neutral and running is usually the rear mainshaft carrier bearing. Rattling when driving is usually either the syncro's going and the gears starting to wiggle a bit, or the shift forks. You can wiggle the shifter a bit and shift fork noise will either quit or change pitch.

If a transmission has incorrect oil, or dirty oil, they will make noise. Sometimes just a good oil change will solve noise problems. Also, adding a bit of moly gear additive will quiet noisy transmissions, but it can also make shifting a bit slower as the syncro's lose friction when they are well lubed by moly.

 

what about while running down the road in 4th or 5th gear, the noise im hearing is in the shifter too. If you hold the shifter while running in 4th or 5th 1800 rpm you can feel it in the shifter. By the way I appreciate your help...