raydar

I finally figured out that my transmission acting funny and my speedometer jumping were connected. Its been acting up for a while now. Most days everything would be fine then all the sudden the transmission would not work right for a while but usally would only be for a few miles and everything would be fine again. It got to the point where i could not drive the car anymore without wreaking the transmission. I put a new transmission speed sensor in. Drove the car out of garage every thing working fine. I thought i had the problem fixed with a 20 dollar part and little time. It drove fine for about four hundred miles with no problem. Then it was a wet slushy day and it start acting up again and it is back to where i cant drive it. I have visually look at the connector and the wire all the way up to top of motor looking for any breaks in the wire and found nothing wrong. Now im stuck and have no more ideals to try. Do i need to keep fallowing the wires more? Is it possible that i got bad sensor or a way to check it? Thanks for any advise