I have a 1998 Dodge Ram 2500 Quad Cab with 12 valve 5.9L turbo diesel, 4x4, NV4500HD transmission. This is MY Problem.

It makes a knocking noise that is coming from the gear box. It does it in every gear and is most noticeable in the peak torque RPM range. When I push in the clutch it goes away. when it is in neutral the noise is gone. The clutch looks fine it is a SACHS that is only maybe 7kmi use and looks brand new. The flywheel is tight and dry as a powder house in the housing. It shifts fine and can be slip shifted with no problem except out of low and second and was the same before the noise. the clutch fork was messed up cause the release pivot ball stud was worn and had a shoddy trail fix on it and all of those components were replaced with new ones including a release bearing from Dodge. when I sit at idle and move the shifter up to the gears without the clutch released it starts to make the noise too. The knocking gets louder and faster as I rev the motor. and again if I push in the clutch it stops. I took off the console that covers the shifter and it sounds like its coming from the center top of the gearbox. And you cam feel the tap/knock through the shifter. I have read the stuff about the fifth gear nut and they always describe gear shifting problems. No one seems to mention a noise prior to that shift problem and I want to stay out of the *Surprise your truck is broke down and now you're stuck with a tow too* club.

 

5th gear backing off doesn't make any noise. It sounds to me like you have a broken tooth on a counter shaft


Ready to be back in a truck

 

Bingo. pulled the PTO cover and raked out half a tooth. ran a recovery magnet in the case and removed a whole tooth and another piece along with iron filings. called High Gear here in Memphis and they had a new unit for a Chevy. They had bolted on the 241HD adapter (Nodular Iron) for a 3500 and installed the improved type main shaft and replaced the fifth gear nut with a locking improved type and Dyno tested. Picked up their recommended fluid with excellent heat transfer and lubricity and Dodge gives a million mile warranty if used in a brand new truck. Its called Delvac 50 by Mobile its a full synthetic that meets the API GL-4 Requirements and I was nervous because of the Dodge requirement but they said that was because of some components they no longer use for the reason that they shortened the life of the Tranny. So a gallon of it went in. We got the old one out and pimped up the clutch case with some Cast iron colored paint and and clear coated the new unit and the red primer on the tail piece and dressed it out.

Pulled the top cover off the old one and on the foremost gear are the spaces for the recovered teeth and a banged up one ready to fail. one the oil was cleaned off the teeth you can see the blueing from the heat glazing. The old oil looked like muddy gear lube about the viscosity of syrup. New one was in and I test drove it by 9:30 PM thank the Good Lord for my two buddies that helped me get the work done in half a day. It was so freakin smooth and tight. I was giddier than a *** with bag of dicks.

Just have a stud on the transfer case to replace cause the old one was wrecked by some unskilled hack that used an incompatible threaded nut. some people got no business wrenching on trucks.