Honda TRX450 FE es Foreman shift issues

I have the following symptoms: I can shift to 1st, nuetural and reverse only and can't shift at all manually. I changed out shift motor with used ebay one and problem seemed resolved till I went through standing water. Problem returned with same symptoms. I ordered the cheaper new shift unit from ebay and once installed it worked great. Decide to cleanup frame redo brakes and new camo job. After pressure washing the issue returned. So replace shifter motor all good till thing get wet. Change shift motor again all good till get wet again.