Changing the antena wire would not cause that type of problem.But if the wires on one motor is reversed it could be causing your problem.I went through a situation like that way back when i first started working on the internals of tanks.Would have pulled my hair out if i had any before i finaly figured out what the problem was.I swaped wires around i don't know how many times before i got it right.Just a guess here.............

If that is the case and one of the motor wires is reversed and you find and correct that then you will still need to get them pluged into the right socket.Good luck and i hope it is something simple like that to cure your problem.

BIGMIG

P.S. With the newer version motors coming out now with plugs installed one must hope they get them right in the factory.But they do screw-up now and then.