RX-350 shifting problem

[Frank in Olalla]

Car sometimes shakes in drive on level ground when not under load, seems like the transmission is confused,  shaking stops when I accelerate or go up a hill  (transmission under load).

[RX400h]

Are there any dash warning lights? You may be able to have an auto parts store check the OBD II port for codes.

[Frank in Olalla]

No dash warning lights, my very basic code reader didn't show any issues.