I have a 94 gt with AODE, it has about 58k miles on it , and a Baumann shift kit. First, second and third gears shift fine but when it goes into overdrive at medium throttle the transmission makes the car shudder/vibrate, but if you have it at a very light, or heavy throttle it shifts ok. What could cause this? My only idea is maybe the torque converter clutch solenoid is going bad, or is it something worse?