rattling vibration noise near driver engine bay at acceleration

[redfusion]

2012 4wd LT 105k miles. Just did both motor mounts and trans mount (GM OEM). When accelerating hard there is a rattling noise usually after 3k RPM. Thought it was a bad motor mount so swapped out with another new one but noise still there.

Seems to happen mostly from a stop or low gears. Any help on how to troubleshoot would be appreciated. The noise takes the fun out of the Tahoe.

 

[Doubeleive]

2012 4wd LT 105k miles. Just did both motor mounts and trans mount (GM OEM). When accelerating hard there is a rattling noise usually after 3k RPM. Thought it was a bad motor mount so swapped out with another new one but noise still there.

Seems to happen mostly from a stop or low gears. Any help on how to troubleshoot would be appreciated. The noise takes the fun out of the Tahoe.

have you checked the wheel hubs? front axles? front diff mounts? front brakes? front suspension?
you are not providing many details

 

[redfusion]

The noise was introduced after the motor mounts. Have not checked the wheel hubs but the wheels were not removed during install. Will check it out.

All new suspension about 6 months ago and it was smooth all the way to 6K+ rpm without any rattling noises.

New cv axles about a year ago around the same time as stoptech brakes and rotors.

It almost sounds like when the ABS system kicks in and vibrates the front except this is when accelerating.

Really lost on this one. Not an easy one to diagnose.

 

[Doubeleive]

The noise was introduced after the motor mounts. Have not checked the wheel hubs but the wheels were not removed during install. Will check it out.

All new suspension about 6 months ago and it was smooth all the way to 6K+ rpm without any rattling noises.

New cv axles about a year ago around the same time as stoptech brakes and rotors.

It almost sounds like when the ABS system kicks in and vibrates the front except this is when accelerating.

Really lost on this one. Not an easy one to diagnose.

well vibration is caused generally by tires/alignment/drive shaft/u joints/pinion. but you will still want to double check the previous things mentioned and anything recently worked on.
it's going to be a process of elimination.
while you are checking the hubs and axles, do a tire rotation or consider having them re-balanced also

 

[Charlie207]

Are your manifold heat-shield loose/rotted, and banging around?

 

[redfusion]

Are your manifold heat-shield loose/rotted, and banging around?

Related but found the issue. I've got long tubes on it and the very back tube is hitting the firewall. The new mounts raised the motor and now not enough clearance at speed.

What do folks with headers use for motor mounts? I see some folks use H3 mounts wonder if those will clear.

 

[Charlie207]

Related but found the issue. I've got long tubes on it and the very back tube is hitting the firewall. The new mounts raised the motor and now not enough clearance at speed.

What do folks with headers use for motor mounts? I see some folks use H3 mounts wonder if those will clear.

The H3 mounts should be the same, dimension-wise as the Tahoe/Yukon/truck mounts.

You might need to whack the primary, Roadkill-style.

 

[Charlie207]

Related but found the issue. I've got long tubes on it and the very back tube is hitting the firewall. The new mounts raised the motor and now not enough clearance at speed.

What do folks with headers use for motor mounts? I see some folks use H3 mounts wonder if those will clear.

What headers are you using?

 

[redfusion]

speed engineering which were a nightmare install too btw but did wake up the engine

 

[petethepug]

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