Why is car jerking and thumping?

[vheying]

We live in central Michigan and own a G37X 2009 Infiniti. The car has 122,000 miles but is in fine condition. It has just had 120K maintenance and transmission drain and flush.

Friday night my wife took the car to do some errands. The car acted so badly that she parked it and we had it towed home. There is no service open in this area until Tuesday. Here is her description of the problem.

I pulled out of the driveway. As I accelerated, I heard a thump from underneath the car. The car jerked to a brief halt (or semi-halt.) I thought it might be snow frozen to a wheel, although snow doesn’t make it clunk, stop or slow, and go again.

I continued to a stop sign. It jerked and thumped a couple more times. I drove about another half mile to another stop sign. The car jerked intermittently. I was on top of a hill and I more or less coasted down the hill, stopped at the bottom.

The car continued to thump and jerk. When I found a place to pull off I did. The motor sounded and acted fine. The tires were not flat. I looked under the car and found nothing. The display did not indicate any kind of problem. No problem was observed when the car loaded onto the tow truck.

Can anyone give me an idea what might be wrong?

[RED_DET]

Sounds like drivetrain issue... at this point it needs to be taken to a shop and put on a lift to inspect.