Thud in the back during acceleration in stop and go traffic.. on 2001 Acura MDX

When I drive for a few minutes and come to a stop at a red light and then accelearate, I hear a loud thud, the vehicle becomes immobile for a few seconds and then starts driving ok. I took it to my local Acura dealer and they fixed the sensor on the left front wheel, drained the transmission fluid, etc but no luck. They say nothing comes up on the computer when the vehicle is plugged in! Any body facing the same problem?

My gut feeling is that the trasmission is quitting but I only have 67K miles on this car and has been gently used. I appreciate any feedback.

Asked by for the 2001 Acura MDX
I'm having the same kind of trouble. I don't hear the thud, but the vehicle has no power for a few seconds, then it's fine. I've been told the transmission is slipping, but I don't think it is. A diagnotician said it sounds like a solenoid. Hope this helps.
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The transmission in my 2002 MDX went out at about 73000 miles on it about 4 years ago so mileage means nothing.There was an unpublished( but printed) Acura Service Bulletin out that a friendly one man garage owner gave me just before he was to order a rebuilt transmission and he told me who to call if Acura would not pay for the replacement. He then told me to go to the Acura Dealer again and say I thought they should replace it at their cost. They said no way so I asked for the phone number of the Western Regional Service Manager and bingo. They immediately said they would replace itat their cost. found it and gave it to me.I still had the Service Bulletin in my pocket
Do you have a link to the service bulletin?