Vehicle vibration when at idle in/out of gear

chevrolet
trailblazer

#1

I have a 2004 Chevy Trailblazer 2WD LS with a 4.2L. It has started a vibration that can be felt in the steering wheel when vehicle is not in motion. It is present in park or neutral, but is worse in gear. I have replaced engine mounts OEM with anchor brand hydraulic mounts and wonder if they were really solid mounts with no change in vibration. I had a mechanic check transmission mounts, harmonic balancer, flexplate, and belt pulley and tensioners, coils and plugs checked. Changed VVT solenoid on engine, used spare throttle body which have helped little but for the most part is still the same. I also recently replaced the brake booster that had a small vacume leak and the fan clutch which had noisy bearings. One thing that I have also noticed a couple of times was during the downshift of climbing a hill at at speed of 65 that there seemed to be a vibration for a few seconds that sounds like gear teeth rubbing a surface I don’t know if this is related or not. Yesterday most recently heard this as well while accelerating onto a freeway. But doesn’t do this on most heavy accelerations in town. Anyone have any ideas it is driving me nuts not knowing if there is a fix not to mention the puzzlement I have with it feeling fine once I am moving down the road.


#2

Is your check engine light on?

If you have a misfire, that could certainly cause a vibration

I have had very bad luck with anchor brand motor mounts, FWIW. Not suggesting that is your problem. Just making an observation

You said your mechanic checked the transmission mount . . .

Well . . . what was the result?

A collapsed transmission mount can transmit torque into the cabin, which will result in a vibration, felt more in gear


#3

I do not have a check engine light on currently, however I think I see it go on and off so quick I am not sure. Checked it with a code reader but have no trouble code found. The transmission mount was checked and was found in good condition.


#4

Went with Anchor brand because of price any others to stay away from saw DEA, Westar, pioneer, SKP, and of course the GM types. Guess you buy cheap and get what one pays for but $94 fir GM seemed a little high when there were others.


#5

As far as I’m concerned, Anchor, Westar and DEA are all in the same category . . . low quality. Over the years, I’ve installed all of them, with bad results in every case

I’m not sure about pioneer and SKP, though. I’ve never installed those