In order to move my 1964 VW Karmann Ghia about 1200 kms (750 miles) I am going to have to tow it on a car hauler, the car hauler weighs 2000 lbs and the car weighs 1500 lbs for a total of about 3500 lbs. My truck is a 98 K1500, 3.73 gears, 18,000 GVW trans cooler, trailer package. Factory manual states the max tow capacity is 6000 lbs.
My question is this; on the flat can I tow in OD, or just leave it in 3rd and put some tape over the tach? I will be crossing the Rockies where obviously 3rd will be used.