Can't stop my hood from vibrating


Original poster
Dec 7, 2011
hi guys,

hate to bring up an old thread but i need some help. i've been experiencing issues with engine vibration. I've checked the plugs (good), checked spark (good), removed/clean TB, replaced both engine mounts and transmission mounts, double checked that all nuts and bolts are tight, but doesnt seem to stop vibrating. I thought I had it when doing the transmission mount because when i lifted the tranny to remove bridge, i decided to start up the car and there wasnt any vibration. keep in mind that the car was lifted by all four tires. also when i put the tranny mount side by side with the new one, the new one had about an inch more high than the original one. after putting it on, i started the car again and it was vibration free, but once i dropped it, the vibration came back. from there i decided to take it to a shop that i know is honest, and i explained to the mechanic what its doing and what i've done, so he took a look and after checking the play on all the pully's, the tensioner and even the fan clutch, which he said was all good, he then told me that since i've already replaced all the mounts and checked everything else that i could alond with his visual inspection, the only 2 things left that can cause vibration to the engine would be either the torque convertor and the harmonic balancer, and that when we noticed that the center bolt on the crank pully was not rotating in a straight circle, it had more of a oval rotation to it. he said that the HB could be going bad and that the half moon pin that goes in the shaft could be damaged. could this be true? what else besides those 2 things can I check for. the vibration is really driving me nuts. BTW, the engine runs fine, it takes off better than before, after cleaning out the TB, but when sitting in idle it just vibrates like a big rig. thanks for the help in advance.


Nov 20, 2011
North Las Vegas
I would take a closer look at the harmonic balancer.

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