Pulling my hair out over vibration/rattle!

[NC Tom]

In Dec. 2017, I had some adjustments made to the timing chain. Apparently, the guide fell off. After that fix, I've had a vibration, but it's odd. I thought it might be the HB, but someone here said it would be constant if it was the HB. It's not constant.

 

What it do:

No vibration in park.

In-gear with brake applied (as at stop light) bad vibration. Hit gas, it stops.

While driving, I hear a cyclical rattle from the engine compartment. Sounds like two or three glass bottle knocking together. It surges three-at-a-time like: rattle, rattle, rattle (2 sec. pause) rattle, rattle, rattle. But, not all the time. It's pretty consistent at around 45 mph. Fades at higher speeds.

 

What's really frustrating is that I can't look under the hood if it's not present in Park. Maybe I could chock the wheels, put it in gear and check, but I'm not a fan of that idear.

 

Anyone run across this before or could it possibly be the HB?

[Pete M]

you don't have someone that you trust enough to not run you over?  

 

if it makes the noise in drive, but not in park, maybe the torque converter has a loose bolt?  

[HOrnbrod]

Pull the inspection cover if you have one and check the flexplate to be sure there are no cracks and the bolts are tight.

[carnuck]

Could the timing chain guide have dropped again? That would be noisy. Is the compression even? I know the 4 cyl is even balanced but the 2.8 V6 could be internally or externally balanced. If external, and an internal balanced flexplate is used, there will be a vibe. Same with Vice versa. Or if wrong harmonic balancer is used. (My old 304 did that with a 360 flexplate)

I guess it helps to know the drivetrain combo.


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[HOrnbrod]

32 minutes ago, carnuck said:

Could the timing chain guide have dropped again? That would be noisy. Is the compression even? I know the 4 cyl is even balanced but the 2.8 V6 could be internally or externally balanced. If external, and an internal balanced flexplate is used, there will be a vibe. Same with Vice versa. Or if wrong harmonic balancer is used. (My old 304 did that with a 360 flexplate)

I guess it helps to know the drivetrain combo.


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Try reading his signature. 

[carnuck]

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[NC Tom]

On 4/18/2018 at 10:22 AM, HOrnbrod said:

Pull the inspection cover if you have one and check the flexplate to be sure there are no cracks and the bolts are tight.

 

More good advice! You really ought to post more. Oh ... wait.

[Gubachoo]

second on the torque converter bolts, seen loose ones make that noise before. Another thing i've done before is not only chock the wheel in drive with the ebrake on, but if you have a wall (i use the edge of the garage with an old tire between) you can put the bumper up against it and have extra insurance against it killing you. Just a thought, but definitely check those TC bolts

[cruiser54]

I would always recommend doing the tC bolts as a precaution anyway. It's quite common. Hell, it happened when they were new!!!!