[CWizard]

When I got into my car this morning, I found the transmission (a Tremec TKO 600) stuck in 1st gear. I say it's in 1st because that's where I left it 3 days ago and also the car drives like it's in 1st. When I last drove it, everything was fine. Even prior to then, there have been no indications of a transmission problem (except for a low volume, high pitched whine coming from the rear that started about 1000 miles ago, and which remains undiagnosed). Now, the shift lever will move from side to side and feels normal when so moved, but it will not go into any gear when the clutch pedal is pressed, regardless of engine on or off. The clutch action appears normal - it disengages when the pedal is pushed and engages when it's released; ie, the car acts just like it normally does in 1st gear. Car has 7500 miles on it. Could this possibly be a clutch problem? Help! And thanks in advance.