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Doug D
03-19-2007, 11:42 AM
Greetings,

I recently had an International Diesel long block put in my K2500. All appears well except for engine vibration that I never had before. It vibrates at idle and at around 3000 RPM. The engine doesn't shake, but it does vibrate. It disappears once you press the throttle, but returns somewhat at 3000 RPM's or so. Oil pressure is good, as is temp. and starting. Any ideas?
Chevylover
03-19-2007, 02:30 PM
Greetings,

I recently had an International Diesel long block put in my K2500. All appears well except for engine vibration that I never had before. It vibrates at idle and at around 3000 RPM. The engine doesn't shake, but it does vibrate. It disappears once you press the throttle, but returns somewhat at 3000 RPM's or so. Oil pressure is good, as is temp. and starting. Any ideas?

What about bad/damaged engine mounts ? Could be some resonance frequency at idle and 3000 rpm. Perhaps at this rpm the engine mounts can' absorbe the vibration and give it unfiltered to frame ? Just a thought.

Cu,
Sven
Violator
03-19-2007, 02:34 PM
A friend of mine had the same problem. Turned out to be a bad tranny mount. Sounds odd but that stopped the vibrations. It coincided w/ install of a new injection pump. We had originally thought it was a problem w/ new pump.
Chevylover
03-19-2007, 02:53 PM
Oh, just forgot that. Like Violator said, tranny mount could be also possible and/or rear driveshaft. As wheel the driveshaft need some weights to rotate smooth. Fallen off ???

Cu,
Sven
Doug D
03-19-2007, 03:11 PM
Thanks for the replies. My mechanic says the engine mounts look good but the rear transmission mount was loose when they took out the old engine, so they tightened it up. Maybe that started the vibration! Anyway, he's going to look over the mounts. He also plans on looking at the harmonic balancer. Keep those good ideas coming.

Thanks
Garth J
03-19-2007, 04:57 PM
If you did any work on the driveshaft make sure the yokes are inline if not that will make a lot of vibration
Violator
03-19-2007, 08:45 PM
Tightening the old mount probably aggravated the worn condition. Instead of tranny riding on rubber cushion, it is now metal on metal. Not good. Driver's mirror probably dancing at idle.