Question Vibration above 2500RPM's?

[SD70M]

Anytime I rev my 94 above 2500, I can feel a vibration in the stick and in my clutch foot. I'm sure they still used the DMF on the OBS strokes.... Could that be where it's coming from?

If not there, would drive shaft balance be the culprit?


Any ideas appreciated!

 

[DaveBen]

The flywheel should never come unbalanced, unless it splits and then you would have one rough runnin truck. I would suspect the drive shaft before the flywheel.

Dave

 

[SD70M]

The flywheel should never come unbalanced, unless it splits and then you would have one rough runnin truck. I would suspect the drive shaft before the flywheel.

Dave

I was thinking that, but it does it in any gear, when I go above 2500... Completely independent of the vehicle speed. Below 2500, it it smooth and purrs like a kitten...

 

[Patrick Feeley]

Can you feel it with clutch in and standing still? It could be the flywheel. Remove the flywheel inspection cover and take a look at it (while you're at it, make sure that the inspection cover is not rubbing on the rear of the oil pan as it can wear right through it causing a leak ... common on 94's). Make sure all the dampening springs and their plastic retainers are there and intact. Take the two masses and counterrotate them against each other. Measure the distance of counterrotation at the rim. If it's more than 5/8" the flywheel is going bad. Cheers!

 

[DaveBen]

I was thinking that, but it does it in any gear, when I go above 2500... Completely independent of the vehicle speed. Below 2500, it it smooth and purrs like a kitten...

I have no idea, now...

Dave

 

[94f450sd]

are you doing this in neutral or with the clutch pushed in?2500 is nearing the rev limit.not smart reving an engine up to its rev limit with no load on it.good way to wipe out bearings or smack a piston with a valve .

does it have a rattle noise when you start,shut it off or at idle?if yes the flywheel is definately junk.this will cause a vibration and can also crack the bellhousing on the transmission.