2006 Z71 Knock From Undercarriage when accelerating from a dead stop
March 10th, 2009, 7:04 PM
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2006 Z71 Knock From Undercarriage when accelerating from a dead stop
I’ve been reading these forums for a long time and I’d figure now since I have a problem I can’t fix I’d sign up.
Problem: When I’m sitting a light, stop sign or slow to an almost stop I only hear this noise. I get a slight knock from underneath my truck. It’s not loud; it’s not hard, but enough that I notice it on a regular basis. The odd thing is this noise does not occur all the time. This is extremely weird, never had anything like this.
What I’ve Done: I’ve checked the brake system, check all bushings to the chassis, looked over the rear diff, and finally the rear brake system.
Thanks for the help…
--Barb
Problem: When I’m sitting a light, stop sign or slow to an almost stop I only hear this noise. I get a slight knock from underneath my truck. It’s not loud; it’s not hard, but enough that I notice it on a regular basis. The odd thing is this noise does not occur all the time. This is extremely weird, never had anything like this.
What I’ve Done: I’ve checked the brake system, check all bushings to the chassis, looked over the rear diff, and finally the rear brake system.
Thanks for the help…
--Barb
March 10th, 2009, 7:33 PM
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Have you done any mods to the exhaust? what kind of noise it? a knock or a clank?
Check your motor mounts and any places the drive train and exhaust come close to the frame. It sounds like when you accelerate the engine twists (because there is so much torque) and is causing something to rattle.
This happened to me after I put my catback system on, one of the pipes was too close to one of the cross members and would rattle during acceleration.
Check your motor mounts and any places the drive train and exhaust come close to the frame. It sounds like when you accelerate the engine twists (because there is so much torque) and is causing something to rattle.
This happened to me after I put my catback system on, one of the pipes was too close to one of the cross members and would rattle during acceleration.
March 11th, 2009, 8:36 AM
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Have you done any mods to the exhaust? what kind of noise it? a knock or a clank?
Check your motor mounts and any places the drive train and exhaust come close to the frame. It sounds like when you accelerate the engine twists (because there is so much torque) and is causing something to rattle.
Check your motor mounts and any places the drive train and exhaust come close to the frame. It sounds like when you accelerate the engine twists (because there is so much torque) and is causing something to rattle.
To describe the sound it's just a knock, not a clank. Sounds like hitting your knuckles on the frame.
I did tighten my torsion bars, but that was over a year ago to level my truck out.
And torque converter???
My thoughts... Motor Mounts?
March 11th, 2009, 11:35 PM
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Yes of course your right...I'll quit while I'm almost ahead. Back in olden times, the motor mounts were pretty crappy. That being said, the tranny mount might look good but have seen them flex enough to make noises....but this is almost a new vehicle. Could it be a slight spark knock?
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March 12th, 2009, 8:14 AM
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I’m not too sure what a “spark knock” is, but it sounds like if you take a hammer and lightly tap the frame. Does that help?
I did notice last night while welding my exhaust brackets back onto my truck, that the driver side pipe is about ¼ maybe less, away from the rear shock. Could this be the knocking? I don’t foresee that making this type of sound.
I did notice last night while welding my exhaust brackets back onto my truck, that the driver side pipe is about ¼ maybe less, away from the rear shock. Could this be the knocking? I don’t foresee that making this type of sound.
March 12th, 2009, 7:19 PM
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The engine can easily torque that much and the shock bell would sound hollow....bet that's it.
Spark knock is the knocking noise made by the engine when suddenly accelerating a large vehicle from a dead stop at idle. The computer almost instantly adjusts for this by adjusting the timing, but you can still get a couple of knocks when you bust one in the butt from a dead stop (and aren't power stalling). Did I explain that correctly forum?
Spark knock is the knocking noise made by the engine when suddenly accelerating a large vehicle from a dead stop at idle. The computer almost instantly adjusts for this by adjusting the timing, but you can still get a couple of knocks when you bust one in the butt from a dead stop (and aren't power stalling). Did I explain that correctly forum?
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