Engine vibration � need help diagnosing

[Rod R.]

[Loren L.]

[Richard G.]

[Greg H.]

Maybe you have the wrong flywheel. The later flywheels were for used for external balancing and may fit an early crank flange? With the inspection cover look at the backside of the flywheel and rotate it 360 degrees and look for a weight mass that is not continuous. If that’s what you see – bingo = wrong flywheel.

[Rod R.]

[Rod R.]

[Loren L.]

[John M.]

[Mark E.]

[Richard G.]

[Rod R.]

[Rod R.]

To clarify-

- the vibration varies with engine speed, not vehicle speed?

- the vibration only occurs between 3500 - 4500 rpm?

- the vibration only occurs with the clutch engaged and the transmission in any gear?

- the vibration stops when the clutch is disengaged and the transmission is in any gear?

- the vibration stops with the clutch engaged and the transmission in neutral?

Does the vibration vary with drivetrain load (e.g., light/medium/full throttle, coasting, transition/no load)?

Mark, in answer to your questions:

Yes, vibration varies with engine speed, not vehicle speed.


Vibration only occurs with the clutch engaged and the transmission in first or second gear as I have not gone to a higher gear at the 3500-4500 rpm.

Yes, vibration stops when the clutch is disengaged and the transmission is first or second.

Yes, vibration stops with the clutch engaged and the transmission in neutral.

Yes, the vibration varies with drivetrain load with medium and full throttle. I can go up to speed and coast, run the rpm up to the 3500-4500 range, and not get the vibration. I have had the engine up to 5500 rpm, no load and it is smooth.

Rod

[Richard G.]

[Rod R.]

Rick,

Thanks for your input. Unfortunately my transmission does not have a drain plug. Sure would make it easier to check the oil.

Normal driving in 4^th gear there is no vibration, nor any other gear. The vibration starts around 3500-4000 rpm, during acceleration, and I am in first of second gear at that point. That rpm in 3^rd or 4^th gear would be too fast mph for the roads I am driving on.

I agree with trying to find the culprit before dismantling everything. I have been down the path of time and money spent on the wrong fix. Thanks for your advice.

Rod

[Richard G.]

With the transmission in neutral and the clutch pedal either depressed or not, I can run the engine up to 5500 rpm and the engine is smooth, no vibration, and sounds good. I don’t want to take any chances of possibly damaging the engine so I have limited the rpm to 5500. The vibration problem occurs while driving and accelerating to the 3500-4000 rpm range (i.e. engine under a load). A couple possibilities could be the harmonic balancer or the flywheel/pressure plate assembly not balanced as a unit.
Unbalance at the clutch would always be there at rpm and get worse as the motor revs higher. I doubt it is the clutch per your testing.

I am leaning towards a transmission, pilot bearing issue, alignment issue.
Rick