Transmission Shudder

Ok, now I been able to drive this 98' SE that I just picked up. It has the 2.4 4cyl and an automatic overdrive transmission. There are two things that I have a questions about with this car. At highway speeds when I let off of the throttle and the depress it again I hear a brief thump. This has only happened at highway speeds so far. The other thing is if the transmission is in over drive cruising at low rpms the car will shudder very breifly when I depress the accelerator. This only seems to happen just before the car down shifts. Does anybody have any idea what the problem could be? I am going to give it a better look this afternoon when my wife gets home with the car.

No need to post your question twice, and please do not bring up threads older then 3 months.

But to answer your trany questions...
I'd check the trans mounts first, then the engine mounts.
If it were an engine mount it would probly the thumpin at idle or low speeds.

Could also be the torqu converter, which could cause the shudder. Also dirty fluid/filter can cause slipping/shudder.
Also check the level and condition of the fluid,
its probly brown frown and smells burnt.

ps I closed your other thread.