1995 Tahoe 4wd, started feeling vibrations through the floor about a month ago. Doesn't matter what speed I'm going, the vibration is always there. RPM doesn't seem to matter much either. Tires are only a year old, and I just got an alignment a few months back.
I once had a 1995 S10 excab that had the oddest vibration. The floor of the cab would vibrate like a drum head.
Originally I thought the problem was due to an engine misfire or a driveshaft vibration.
I pursued every friggin' possible source I could conceive.
The problem turned out to be the bushings mounting the cab to the frame. The metal parts on some (not all) of them had rusted-out and they were no longer affixed to both the cab and frame, so neither cab nor frame was firmly affixed to the other as designed. Replacing the rusted hardware and bushings quieted the cab down a LOT.
I'll never forget that lesson.
FWIW, that was an IL-driven S10, so the cab bushing mounts saw winter salt.
How did I discover the problem? One day I found a rusted bushing retainer (a new one is pictured below) lying in the driveway. Evidently it had rusted enough in the center that it fell off the head of the retaining bolt, and just happened to fall where I might find it. I then looked under the truck and found others were missing as well.
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