Braking produces klunking noise

Hi there,

One of my jeeps, a 2000 grand cherokee limited V8, have all of a sudden started to make a noise when I hit the brakes and I would like to get some thoughts about what is going on.

This car has a automatic transmission.

When driving (slow or fast) and if I just hit the brake pedal (just half an inch) I hear a klunking noise from under my car.

This only happens when the car is in Drive (park, reverse, neutral - nothing happens). If the car stands still, nothing happens. When I'm driving and I barely touch the brake-pedal the noise is there. I can rapidly hit the brake pedal to reproduce the noise every time.

I changed the transmission fluid this summer and have been driving alot since then without having any problems whatsoever.

Anyone having any ideas?

bjornw>
1996 - Jeep Cheroke Limited 2.5TD
2000 - Grand Cherokee Limited 4.7L V8
1967 - Plymouth GTX - 7.2L V8

Does it sound like its coming from the trans... or just under the vehicle somewhere

Is there any kind on clunking when you accelerate from a stop, I would get under there and twist the drive shaft by hand to see if there is any play in your joints. If there is no play then see if twisting the shaft will duplicate the noise to try to isolate it..

I had the same problem but it worsened. It turned out to be a bad u-joint.To check it do what whatever mentioned. Also you will probably have to put the trans in neutral before trying to check it for any play.

The noise only happens when the car is moving. It doesnt matter if I drive fast or slow. If it happened when the car was at full stop, I would have an easy time locating the exact position of the noise.

I will test the U-joints this when I get back from traveling (in 2 weeks).

What I'm really afraid of is if this noise comes from the transmission.

If you say it sounds like it is coming from the transmission area, you could check the tranny mount. grab the front of the rear DS and try to move it around. See if the TC and tranny have any movement.

There was a video someone posted in a thread from last week here showing movement that would require a new mount.

yep heres the thread with the video brokensockets was talking about

http://www.naxja.org/forum/showthread.php?t=1055901

Also check your caliper bolts.

Just an update.

This klunking-noise appears before the brakes kick in. I can just touch the brake-pedal to produce this sound. E.g. I dont push the brake-pedal down enough to let the brakes start to slow down the car at all. Is there any sensors connected to the brake-pedal in such a way that they will react and do something when I start to push the pedal?

The sound, which I can hear and feel, sounds like it comes from right under my seat/feets.