I was sitting in traffic when I heard a bizarre croingggg noise ( cross between a creak and a broken spring noise) and felt a clunk from underneath the car. I thought that part of the transmission must have snapped or something. There were no CELs luminated, so I gingerly gave it the gas. It seemed to drive fine, but the transmission has developed a surge while shifting. Something definitely broke somewhere to make that noise. I can imagine myself going to the dealer and telling them to check under the car for a missing spring or something. My experience with them in the past is if it is not showing any codes, there is nothing wrong. Any guess to what this could be? I would like to be able to point them in some direction or have them make a note at least on the paperwork. The noise may not have anything to do with the transmission surge problem, but it is sure a coincidence.

 

Could it be the drive shaft coming free in the middle? Support bearing failed. No noise makes these unlikely though.

 

does the gear shifter move when you accelerate hard, if sounds like you have a broken motor mount(s)

 

My drive shaft was replaced 3 weeks ago due to the bushings going bad. The clunking sound was prevalent when accellerating hard.

 

Not that I have noticed. When the transimission shifts, there is a small
surge. I started noticing it at 70 MPH, it would surge down when slowing,
or up when accelerating. It is so noticeable I always look at the dash thinking
something is going to light up - that is how I noticed it was always at 70 MPH.
Now it is surging while shifting at other speeds.