NeedForSpeed

Recently I brought my car back to the dealer because my engine/steering wheel would shake and shiver in both sport shift and auto (shaking slightly not as noticeable) when shifting from 2nd to 3rd and from 3rd to 4th at about the 2500rpm. So I took it down to the dealer and they also don't knowwhat the problem is and suggested that they order a rebuilt tranny for me which would take about 3 weeks cause they are on backorder. I was the one that told them it feels like a tranny problem to me and my auto knowledge is pretty limited and was just a guess on my part. After this incident I have a few questions myself to you fellow members.

1- Has anybody on this forum ever experienced this to their car?
2- Does anybody know what might be the problem?
3- Has anybody had their tranny replace with a rebuilt one from the dealer? Does it feel better and does it run like new?

P.S. - My car has about 24,000 miles on it