Vibration

[Fry]

I have a 94 6.5 2500 4x4 manual trans. At about 2100 to 2200 RPMs I have a vibration. This vibration then goes away when it passes this point and runs perfectly smooth. This is felt in all gears and is the same every time. I have had the tires balanced as a starting point but do not know where to go from here.

[DmaxMaverick]

I'm surprised you haven't received a response here yet. I'll take a stab at it.

If the vibration happens at a specific RPM, in all gears (or just more than one gear), you can rule out anything rear of the tranny input shaft. If it were after the input shaft, it would vary the RPM, or be consistent with road speed, not engine speed. There are several possibilities.

1. Harmonic balancer.
2. Isolated (dampened) crank pulley, if so equipped.
3. Accessory belt.
4. Accessory or pulley (A/C, alternator, PS pump, water pump, fan blade, etc).
5. Pilot bushing/bearing. Very common with the roller bearing.
6. Dual mass flywheel.
7. Clutch/pressure plate. Could be loose, broken, or have hardened/cracked, or missing isolators.
8. Tranny input shaft. Spun race or bearings went south.
9. Exhaust system making contact with chassis. Worn, bent or missing hangers/rubbers.

There are numorous other possibilities, but this should be a good list to start with.

With your next post, try to be a little more detailed. Where does it sound/feel like it is coming from and what does it sound like? Metalic, marbles in a can, thumping, sharp, dull...?? Anything other than RPM that changes the sound/feel (load, unload, power, compression)?

Good luck.

[Fry]

It was the flywheel.