I have started to notice that I sometimes hear a light metallic thump when I give the car gas from a standing start. It isn’t a grinding sound but rather a sharpclick. But louder and more distinct than a simple popping of hot metal that you sometimes hear after turning off the engine. It doesn’t happen all the time and in fact may have been happening for a while and I just did not hear it over the radio. It seems to be coming from underneath the front seats or slightly to the rear of that area. It can happen at any time, when I change from reverse to drive after backing out of a space or just starting forward from a stop sign or light. And I am not talking about stomping on the gas, just normal acceleration.Like it is dropping into gear or something, but from a standing start?

Should I be concerned? Is this a precursor of some transmission trouble? Differential?

2005, 3.0, auto

Thanks

 

Could be anything..My first impression from the title of your post was a U joint in the Prop shaft..then after reading your post, it sounds more like maybe a CV joint..Get it checked out.

 

this may sound stupid but, have you looked under the seats? to make sure there is not just someting rolling around hitting the bottom of the seat?

 

The last time I heard a sound similar to what you're talking about, the damn transfer case took a **** on me about a week later.

Every time I started from 1st gear, it would go "click". I noticed it one day when I was at a drive thru and I could hear it very distinctively. I knew it was the transfer case because when I had it replaced, I went back to a drive thru, and I never heard the noise again

I'm not saying that's what it is, but if the shoe fits...

 

its the CV joints. I have the same problem and had the same problem when i took it to the dealer but they said they were not near bad enough to replace. I am sure i will have to buy halfshafts soon but until then i would just drive it.

 

I have replaced CV joints before but they were forward of where this is and with bad CV joints I only heard the clicking noise when turning, and it was a repeating click. It had nothing to do withthe initial start of movement. I find it hard to believe this has anything to do with CV joints. I have seen worn out CV joints and experienced them.

let me try this again:

The noise is intermittent. It does not always occur. Sometimes it will happen and then not again for the remainder of the trip
It can not be heard over the radio or even the air conditioner, you have to have silence to hear it
it is one noise, not a series of them. one distinct clunk with a metallic sound to it
it happens when you start from a standing stop, when the car is accelerating, but not when it is changing gears. It upshifts later
it is not affected by hard or slow acceleration
it sounds as if it is coming from between the front and back seats, sometimes in the center and sometimes behind the driver's seat
at first I thought drivetrain. transmission seems unlikely as it does not seem to be associated with gear shift points

The car only has 19000 miles on it but it is three years oldthis month. I will be taking it in for the 30,000 mile prepaid service and will have them check it then. As I said, it might have been doing this for some time and I never heard it over the radio

 

Great analysis Tar..you should have put it that way in the first place...

It very well maybe the Transfer case then..sounds like it could be gear lash..
Try backing up and then put it in drive..see if you hear the clunk doing that.

 

Thanks Dennis. Yes, I have heard it when backing out of a parking space and then putting it in drive, but not all the time. Maybe one in every 10 times.

 

Go underneath and twist the prop shaft back and forth and see if you hear a clunk while doing that..I'm think it also maybe your U-joints..at any rate, this may help you pin point where the noise is coming from.