2001 civic ex automatic transmission
 

I recently had my timing belt and transmission fluid replaced. I was not having any problems only that it was time to be serviced.

Honda tech said I have a cracked front motor mount and torn compliance bushings.
Now when I put transmission in reverse car vibrates. Seems to be in the transmission. It disappears after the vehicle warms up. I also noticed the transmission seemed to take longer to shift from 1st to 2nd gear also until warmed up.

I asked if they might have put the wrong transmission fluid in but they want to blame the engine mount.

Any thoughts?
Thanks

Given that the annoying vibration disappears when the engine is hot, you may want to check whether the engine idle speed is set a bit too low. In addition, when the work was done, the mechanic likely disconnected the battery. This would require the ECU to relearn the proper idle. Perhaps with more drive time the problem will go away.