Cobra 25 issues

I have a cobra 25 that i was given. Had to replace the reverse polarity with one robed from a dead radio. Hooked it up in my log truck to test and it seems that every bump i hit causes the radio to try and key up. It is almost a constant clicking sound.
I have been running radios since i have been able to drive but never really worked on them. Any thoughts on what i can check or do to try and resolve? Thanks for any input.

 

I used the mic on my daily talker. Could it act differently on separate applications?

 

Not having the correct tools/knowhow to trouble shoot it is aggravating. I prefer to do my own repairs across the board.