The Toyota Matrix, 2006, XR, Electronic Shift, shows a "bump" when the car is heated, after driving ten minutes, upon upshit. Electronic Transmission.

Downshift is o.k., all shifts o.k. before heated, then "bump" after warm up. I'm thinking maybe air in tranny fluid causing weird pressure in line. But, the fluid, measured hot, is above the max fill line. Toyota dealer did service in May, two months ago. Could this be culprit.

Also, shifts fine when cold including accelerations, declerations, etc. Only problem is the firm bump when hot.