Widowmaker[X]

Hey guys,
My son's 03 V6 is having what seems like a transmission issue. I fear the worst but I figured i'd see if anyone has had the same problem.

The problem occurs when shifting from park through or to the reverse gear (its an automatic). When passing through R to get to Drive, there is sometimes a fairly noticable thumping noise. It is not a grind or anything like that, more or less a thud. Sometimes it is loud enough to feel sitting in the car. I have shifted back to park and shifted through reverse again, with varrying results. Sometimes, the noise is there, sometimes, it isnt. The noise only occurs when going from park to reverse, not from N to reverse. I took the car to my Ford dealership, only for them to have 4 mechanics and salesperson look at it and drive it and find no aparent issue. In drive, the car shifts fine with no problems, but I fear ignoring and living with the problem will lead to serious transmission problems.

Any ideas are greatly appreciated.

***EDIT, HERE IS THE VIDEO***

Ok, here is a video.

I shift from park to drive four times. You can hear the thumping noise. After watching this video from underneath the car, it sounds like something is rattling pretty badly when the car is in drive. You can hear it in the video.

http://youtube.com/watch?v=djNp6Or8J_8

Colorado_Mustang

Has the tranny been serviced (fluid and filter)? How slow do you have to shift to make the noise?

I'm assuming the mechanics made sure the tranny/engine mounts are good and that the u-joints in the driveshaft are tight.

Widowmaker[X]

Ok, here is a video.

I shift from park to drive four times. You can hear the thumping noise. After watching this video from underneath the car, it sounds like something is rattling pretty badly when the car is in drive. You can hear it in the video.

http://youtube.com/watch?v=djNp6Or8J_8

Chopper

It could be a loose part in the exhaust that comes alive when the lower RPM of the engine,due to tranny engagement,hits the correct resonance frequency.
However,it seems to have a "ratcheting" type of sound instead of the "tinny" rattling quality of exhaust problems.

How does it drive?
Does thenoise go away when the car is moving?
Can you raise therear of the car onto jackstands and let the tires roll while the car is stationary to try to replicate the sound?

With the car sitting still the only things in the trannythat could be making noise should be the pump and the torque convertor.The torque convertor has vanes inside that while in nuetral are all spinning in the same direction,atabout the same speed.When you put the car in"drive" the vanes on the impeller half are moving and the vanes on the stator are stationary.The sound could be coming from some of the vanes coming in contact with each other.This sound should (?) go away when the torque convertor locks up when driving.
The pump part of this answer is just another possibility but I think it is unlikely.
Without being able to actually listen to and drive the car this is the best I can do.Sorry.