My jetta gls 2002 automatic transmission not changing gears, parking, reverse, neutral works but drive is stuck in 2 gear and wont change !!!
My car has an automatic transmission.
The internal transmission shifting mechanism of the valve body to the forward clutches is not working, or the forward sprag clutches are broken. Only a transmission pressure test would be able confirm if the problem is in the valve body or the gears and clutches inside of the transmission.
The most common failure would be the gears and the transmission would need to be remanufactured or replaced with a used one that is good. A certified mechanic will be able to diagnose your gear problem and find a fix.