the accelerator is applied the whole truck shakes! Any suggestion!

 

Auto or manual? Why was the tranny replaced? Was the torque converter replaced with a brand new one? Flex plate? Is the new tranny brand new or rebuilt?
Sounds like you need to check the alignment of the torque converter to the flex plate.

 

Definitely need much more information...

Have you checked your motor mounts? Who did the replacement of the transmission? Can you accelerate at all? Is it tied to throttle or ground speed?