LS1Steve

If an OEM damper is bad, is the vibration felt during a neutral rev AND when revving up under load?

Is it possible to be perfectly smooth in neutral (or w clutch down), yet bad vibration in gear accelerating under load?

9t8z28

iTrader: (19)

Stock balancer? Mileage?
The bolt holding it on usually gets loose and then the balancer wobbles. Take a look and see if it wobbles while the engine is running.

runsfromdacops

mine would squeak as the pulley worked its way off.

if it still has all the rubber in it and the outside isnt wobbling independent of the hub its fine

LS1Steve

Its an OEM balancer that was replaced only 8k miles ago, however I did an engine rebuild after it was replaced, so it has 3k on the 'bad' engine and 5k after it was removed and replaced on the rebuilt engine.

Is it feasible that it could only show symptoms when engine is under load?

RADEoN

iTrader: (12)

No. I think it sounds more clutch related, tbh.

DACTARI

iTrader: (1)

yeah, it's felt whenever you rev.

it won't be the dual-mass flywheel either because that rotates with revs too. probably something further down the driveline.

LS1Steve

Per my other thread, new engine, newly rebuilt trans, good diff, new driveshaft, new mounts, dual mass flywheel replaced with a balanced LS7 clutch. Noise is in sync with the flywheel side of the trans. Dampener is literally the only possibility left, but just confused why it the noise/vib would occur under load.

heavymetals

iTrader: (3)

Now you are getting into everything that is on the front of the motor.

Could be power steering pump, alternator or even A/C compressor (even if off).

Cadzilla

iTrader: (3)

How bad are we talking? I had a very similar pattern of symptoms. It was certainly engine related but seemed to be more in rear the clutch...it vibrated bad. In neutral, under load, whatever. Seemed like an oblong/egg shaped orbital up/down vibration.. My hand would go numb on the shifter, the rear view mirror looked like I had 18" subs in the trunk.. my headrest shook and the passenger seat even wobbled as I drove.

I recently replaced my stock balancer with another stock unit to rule it out before I went after the clutch. The one I replaced had <10k but still seemed to visually 'wobble'. The new one does the same thing, and I followed the install instructions to the tee using the right tools. Prior to the balance install I also pulled my mounts to rule them out as the culprit. Lastly I removed the accesory belts and cranked it just to be sure..

I just replaced the clutch with the ls7 setup. and the vibration is gone. I noticed before removing the old setup from the engine that all the fingers on the old pressure plate were bent bad outward much more on one side than the other. It could have been that I didn't torque all the pp bolts down the right way last time, and/or the fact that I reused the stock bolts and not enough/or too much red loctite. I'm guessing it was (not only that POS flywheel) the pressure plate not working correctly.

I know you already have the LS7...so could be a botched clutch install? Thats my only guess unless it's something accessory related. The vibration in neutral rules out everything south of the trans.

DACTARI

iTrader: (1)

It's not clear from the initial description, but he appears to be saying he gets the vibes only under load.

runsfromdacops

bad pilot baring ?