Darknesss_TL

Haven't heard or seen anyone bring this up but after I start the car and put it into drive and accelerate i hear this strang sound like a "clunk" or a "thud" sound about 15-30 seconds after first putting my foot on the accelerator and it sound like its coming from underneath the car or below the engine where the transmission is....anyone else have this issue?

dryburgh

I don't have the AT but I have a similar issue on my '06 TL. On a cold start (i.e. car has been sitting for a few hours), there will be a single clunking sound as soon as I hit 30km/h. It always happens at exactly 30km/h and it only happens once. It doesn't seem to matter what gear the car is in (although, realistically, I think I've only tried first and second). After that, the car has to sit for a few hours before it will happen again. The noise sounds like it's coming from somewhere up front and I can feel it through the pedals.

The dealership has not been able to reproduce this, mainly because they're located on a very busy street, so by the time you can pull the car out of their lot and get up to 30km/h, it's too late - the car is too warm. They suggested a few different theories, like the Brembo brakes shifting after sitting overnight, but none of their ideas explained how I could feel the clunk through the pedals.

Other than this, the car drives well.

ndx2

It's probably the ABS self-check, darknesss.

mrodriques

Are all of your pets accounted for?

1995hoo

To the two original posters, check the 3G Garage thread on the main board. This is addressed there. As ndx2 says, it's the ABS check and it's normal.

vc123

my 5 months old tl has that sound too
it really annoys me and i can FEEL IT on my gas paddle too it doesn;t happen when it;s warm or hot it happens when it;s COLD

1995hoo

It's normal to hear the thunk, but it's also not unusual that you don't always hear it. See the thread below, which I started not quite two years ago. At the time my thunk was less noticeable. Nowadays sometimes I hear it, sometimes I don't.

https://acurazine.com/forums/showthread.php?t=107082

Bammyz

I posted about this same topic a few weeks back. I believe it is the ABS (as others here have said).

The same thing happens to mine when I first start it (cold start), but that is the ONLY time it does it. After the engine is warm, it doesn't happen.

punkin

I have been reading this post for almost a year now and have the very same problem (cold start, 18-20mph, one time only). Bought my TL (AT, 06) in October of 05 and noticed the "pedal bouncing" and sound soon after purchase. I did not notice the "pedal bounce" and noise during the winter months (2 of them now). It reoccurred with spring, lasted all summer and fall. After living with this for almost 2 years, I have drawn the conclusion it is tied to the AC auto climate control. Now that I have 35k miles on my car, the AC upon starting makes the same sound and has "bouncing pedal". I believe the auto climate control is tied to a speed minimum (18-20mph) and what we are feeling is Auto climate control related. If anybody out there knows whom to ask about this speed minimum theory, please do.

I ALSO have encountered the same BS with the local dealer not being able to (wanting to) help with the diagnosis. I also called Acura corporate for help – more BS.

Darknesss_TL

i haven't been back to this topic in a while... since i've had this car, it starts up EVERY TIME, cold start, even after i've been driving for a while and the engine is already warmed up, as soon as i shift the car into DRIVE, and accelerate that thud happens EVERY TIME...i've learned to live with it but i guess everyone has their own theories about it... i have to go to the dealership to get the oil changed in a couple of weeks...perhaps i'll have someone sit in the car with me so they can hear it for themselves... who knows... thanks for all that have replied