2007 Hummer H3 deep vibration in the motor

Is it a vibration when driving?At high speeds?Low speeds?When taking off?In 4wd?The whole vehicle?Front end?Rear end?Could be a number of things. Before diagnosing I would call the dealer and tell them you have 36,000 on it but have a vibration problem and the dealer might goodwill the repair, most dealers are pretty fair about goodwilling vehicles that are just out of warranty.I would call them first they might help you out at no cost to you. If they do not help post back and I will help as best I can.

Only help I can give is, check the engine compartment for any p/s lines making contact with the firewall or any lines making contact with the engine, this will cause a vibration. If so move the lines out of the way and see if it goes away. If not could be alot of things, like an internal engine vibration which could be crankshaft out of balance, could be a alt, p/s or harmonic balancer out of round. Could be an engine/trans mount loose of moving. You did not say if this vibration is happening when the vehicle is moving.I"m sorry but I can only advise so much, I"m not there to see the vehicle, vibrations are very hard to diagnose. If all else fails for a fix the only other thing is putting on the eva, which is the electronic vibration analizer which is a hand held tool that only the dealer has, but this tool will find the source of the vibration. I have used this tool before and it does work, only problem dealer are the only ones with access to it. Try the above suggestions and post back with what you find and will advise from there.

A few things come to mind in an effort to diagnose. Remove the drive belt, that would eliminate the accessories, and run the engine up to see if vibration persists. Not too long, don't want an overheat or dead battery. The next thing would be to disconnect the torque converter and run the engine up again. The latter is easier said then done, it is pretty tight. A thin, long, 0 offset box wrench is about the only tool that accomplishes this aside from removing the starter(which isn't fun either). I assume that there is no check engine light on, a misfire would cause a vibration but would also trigger the light.