What is the recent service history? Is the check engine or "OD off" light on or flashing? What is the condition of the transmission fluid? Is it red? brown? smell burnt?
What happens if you put the gear selector in the "2" position?
It is possible that the throttle cable is not adjusted properly. If not, more thorough diagnosis with trans pressure gauges is in order.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.