Electrical problems on my 2001 ZX3

[HJobe71h]

Well.. I hope you all can help me.
I've taken my car to the dealership twice, they've given me the run around.. charged me tons of money for "something that is not covered under the warranty" when they don't even know what the problem is, and I really hope that someone here has seen this problem before and knows what it is.
No matter what speed I run, no matter if the cruise control is on or not, while driving my car slips out of gear and into neutral, then goes back in. All the while doing this, the lights go out, the radio skips and all signs lead to an electrical problem. When it was at the dealership they said a mouse nested in there and chewed wires but yet they didn't see any but still charged me. My mechanic I use went through the whole car and didn't find ONE single wire that had been chewed. He checked the alternator, no problems there. We thought the transmission problem was due to low fluid, after we topped it off it was doing the same problem again. I'm really not sure what it is, I thought it might be something with the battery. Maybe it is corroded or has a short in it. Everything is up in the air but I do know that I will NEVER buy a Ford again after the problems that it and the dealership has given us. So if anyone out there can help, it'd be appreciated.