Clunking sounds when shifted to Reverse? - 1

Hi, Can anybody tell me what could be the reason for this clunking sounds when i shift the gear from drive to reverse? My hydraulic mount near the power steering oil is new, my engine mount on lower is also new, my transmission mount is also fine as per the mechanic(honda), clunking sounds can be heard during shifting to reverse from drive, sometime i can hear noise(slight clunk) when accelerating (i can hear only this during automatic shifting(decelerate) when gear from 3rd then it will automatically shift to 2nd gear & then when i accelerate, mechanics from honda told me that this is clunk sound normal, but i'm not satisfied to his answer, when AC is ON, and whenever condenser fan will work i can feel 0.5sec slight vibration, can anybody help me on this? (H-c.i.v.i.c.2008-AT-transmission)

Added (1). Mechanics told me that Transmission mount, Engine mounts are fine, i replace also the lower engine mount but still clunk is there, CV joint also fine(we remove the old grease and put new grease on it)

Could be this normal? No vibration, no clicking sounds or what ever, just the clunk sound when i put gear on reverse from drive

Lose/worn U-joint in the drive train somewhere.