2004 TDI Beetle Speed Sensor Problem

[Pooh105]

I bought a used 2004 TDI Beetle in Feb. 2010 with an extra 2 year 24,000 mile warranty (preferred coverage thank God!). After only 3 weeks, while driving the car the transmission (automatic) would surge in rpms while in 6th gear. I found this strange as in a couple of days, the car would do this in any gear, including acceleration from a stop. I took the car back to the Dealer. They informed me that they could not reproduce the problem and that the computer showed no faults (that should have been my first clue). The car ran fine for another two weeks and the problem started again. So, back to the Dealer and I got the same response. No reproduce, no computer faults, no can help you. after another two weeks (I fly a lot for the GOV) I said the heck with it and took the Beetle to a private mechanic. It took him two hours and he found the fault. A code 17100 - Transmission Input Speed Sensor (G182): Implausible Signal P0716-000---Intermittent.However, the mechanic was honest in telling me that he was swamped and it would take over a week to do the car. He suggested to take his findings back to the Dealer and let them fix it as they sold me the warranty. I took the car back to the Dealer (University VW in Albuquerque) and guess what? "We do not except outside mechanics diagnosis". Again, no reproduce, no computer fault, no fix. I'm at wits end here and need advise. Is the private mechanic a better choice or am I just hosed? Also, does anyone know what the cost would be on replacing the Speed Sensor? Thanks for the advise!