So this week as im starting my truck, I pull it into reverse, release the e-brake and as I take my foot off the brake and begin to back up, I hear a loud "knock" from underneath my car. I also feel a slight vibration as it knocks. It ends very quickly, and runs fine after that. It only seems to happen when the vehicle is cold, if it is running and I go into reverse from park it shifts smoothly. I have also head the knock once going into drive. Not very loud and it doesnt seem to be hindering the vehicle at all, but very annoying and as you imagine I am slightly concerned.

I will be calling the stealer if it continues and make a apt. for a service check. It is still under powertrain warranty.

Specs are 3.4 SR5 4WD 1997 with around 84k

If anyone has had this exp. or has any advice onto what the problem could be, a reply would be MUCH appreciated.

 

First thing poped into my head is a bad/worn U-joint. Check to see if you have any play/sloppiness. I could be way off, but worth checking anyway. Good luck.
butnut

 

I'm not sure it's your tranny. But, check and make sure your fluid is at the right level. Can someone listen from outside the truck. Like Butnut said, sounds more like a u-joint or something like that. Good luck.

Pete

 

The only times I've heard *clunks* is when I've switched from 4 wheel drive to 2 wheel drive before pulling into a parking space. The 4 wheel drive didn't disengage fully, and when I left the parking space, it clunked while backing up.

 

My 92 clunks pretty good when I go from reverse to drive! It clunks also when going from park to drive, just not as much. It seems as if going into or going out of the reverse gear makes the biggest clunk! Just a thought.... :fireman: