Knocking under floor board
 

What it do, y'all?...I just got an '04 Monte Carlo LS about a month ago and noticed that immediately after I switch gears and give it some gas, there is a very dense knock under my floor boards (both front driver and front passenger boards). I took it back to the dealership for warranty work, but they came to the conclusion it was a natural noise. I took it to another dealership for a second opinion and they told me that its the first time they heard the noise from a MC, but checked all of my mounts (motor and transmission) and my suspension and everything checked out fine. They called GM's mechanics tech support for potential recalls, but they also told the second dealership that everything was fine and that it was a natural sound. I test drove two 05 MCs and don't hear the sound. A mechanic in the second dealership worries that it could turn serious overtime even though its supposedly a "natural sound" due to aluminum parts and slack. Has anyone else experienced this problem; if so, what route did you take???

RE: Knocking under floor board
 

wassup i have a 04 mc ls as well and it has about 44000 miles onit and it has yet to even make such a noise like that? how many miles are on yours and how long have you owned it?

RE: Knocking under floor board
 

I just had it almost a month, and it's been doing it since about the first week I got it. She's only got 24,000 miles on it.

RE: Knocking under floor board
 

If I were you, I would keep taking it back to the dealer. This will establish a strong history of your issue with it.

I would have them check the connection points of the aluminum motor tray. I've heard of these things warping leading to some pretty serious alignment/noise issues.

Did you by any chance remove the three strut braces in the engine bay for painting or detailing? I've also heard of these things making a popping sound if they are not secured.

TVW

RE: Knocking under floor board
 

I appreciate your help, T...I never got it painted or detailed, so as far as I know, the three strut braces were never removed. But they never told me if they were checked or not. All they told me was that they checked the mounts, both motor and transmission, and that everything in the suspension alignment was alright. Is the motor mounts and/or transmission mounts related to the strut braces?

RE: Knocking under floor board
 

i think it is all those ponies trying to get out!!!

RE: Knocking under floor board
 

Out of curiosity, how many miles do you have on it??

If the sound were easily duplicated I would make the service writer ride with you to pin point the exact sound in question. Persistence pays.......

I would even go as far as to ask to drive another new one to ensure it's not making the same sounds yours is.

I would also check the firewall for any thing close causing bang/scuff/abrasion markings. Maybe as the trans shifts something else is hitting/rubbing the firewall. Next thing I would do is while the car is off and cool check out the entire exhaust system for loose hangers and or mounts.

This one has me a little confused...... First they noted the sound was something they never heard before from a Monte yet everything is ok and it's a natural sound..... I would have called them out on that one... lol

The bottom line is they should not be happy till your happy.

RE: Knocking under floor board
 

when i worked at a dealership, if a customer who wasnt served to their happiness would make a comment about contacting the regional HQ..we would BEND OVER BACKWARDS....so if they dont help you..ask for a regional office or regional manager.

RE: Knocking under floor board
 

Well I work at a Chevy dealer here and I havent heard of this knocking either. I asked our steering/suspension guy and he said may be the intermediate strg shaft in the column or possibly the suspension cradle...bushings worn?

RE: Knocking under floor board
 

[sm=icon_rock.gif]

What exactly do you do? We may have found our inside guy......

hehehehe... [sm=badbadbad.gif]

I had my ISS replaced; I know that sound very well. I normally heard this when hitting a bump or turning and not at shift points, but anything is possible. I don't remember feeling it in the floorboard either it was more in the steering wheel/brake pedal. That being said, if it resonated through the steering wheel it could very well resonate through the floorboards as well..

Tell your dealer there is a TSB out on the ISS and you would like to have it check out for a possible ISS replacement. DO NOT SETTLE FOR THE RE-LUBE DEAL. For those that don't know what these are.

TSB = Technical Service Bulletin
ISS = Intermediate Steering Shaft "AKA the dreaded clunk...."

FD may be on the right track here..


Is there a TSB on this one FD?? Can you ask your guy if this has been a known problem area with the Montes?? [sm=interesting.gif]

TVW