Originally Posted by tharber

I might suggest that you remove the serpentine belt briefly and see what happens to the vibration. This will eliminate power steering and a/c. Don't drive it, just remove the belt and see what happens. There is a tension and idler pulley that if they were to go bad could cause this issue too.

I have added a generic pic to help explain:

TH

Originally Posted by Synthetickiller

We did the belt today... it didn't point us to anything specific.

Originally Posted by flyday58

Ask your local mech what he thinks about the flex plate. Or she. Not trying to be a feminininininest here...

Originally Posted by Synthetickiller

Alright, I have the H2 back & took it for a 40 minute drive. Symptoms have changed, somewhat.

The replaced engine mounts fixed about 90% of the vehicle shaking when in park or neutral. It's there, but barely. Once the trans is engaged (drive or reverse) with a foot on break, you can feel the vibration again (in the shifter, pedals, steering wheel, & floor. Not so much in the door, arm rest or as much in the center console like before.). Reving the engine doesn't increase the vibration at all. It's almost the opposite at times, strangely.

Also, when the compressor kicks on for the HVAC, I feel more vibration while it's working. Also, the vibration goes through cycles, almost mimicking what the engine is doing, but indirectly. Also, the tires still vibrate, even when in park, but not to the same degree.

The motor mounts fixed a lot of clunking going on when accelerating, stopping, slowing down, etc. The total amount of vibration is lower too. Acceleration is better. The H2 doesn't lunge forward after taking the foot off the pedal awhile accelerating. I'm able to give it more gas & keep the rpms between 2500 - 3750 while giving it lots of gas. I was unstable to do this before. The vehicle felt too floatly. Now it feels planted, besides this stupid vibration.

Listening to the exhaust, it's not a misfire.
When the engine goes through different cycles while being in a stopped position (in drive, foot on break), the vehicle will shake in different ways. I'm wondering if a bolt on the exhaust or something is loose/broken...

It's shaken for a long while since I've had it, but because everything suspension-wise on it was shot, it was "background noise" so to speak. Take into account that all the bushings, ball joints & motor mounts were bad, I'm guessing anything that would secure whatever is moving has or broken off or worked it's way loose (probably a bolt).

I'll have to get under it sometime & take a look.

Originally Posted by mcioci

I've had broken manifold bolts on both my trucks and there was never any vibration just a ticking sound until engine got warm then noise would go away. So you have a brush bar on the truck? Cage? I had a brush bar on my 05 and I had vibration to lo esp in pedal and seat, my kids would feel it in the back seat. The brush guard was mounted and there was metal on metal apparently and whole truck vibrated. It may be a long shot but it's easy enough to remove to see if vibration goes away. Best thing to do is get it back to stock on outside of truck to eliminate something as stupid as that.

Originally Posted by certz656

I've heard of the front harmonic balancer going bad, the hard rubber can separate causing an unbalancing effect and taking off the belt probably won't change the vibration since it is directly running off the crankshaft. Just a thought though..