My car has a manual transmission. It will not shift out of gear. It appears to be stuck in 2nd gear.
The clutch pedal feels and works fine.
The car has only 74k miles on it.
Could it be the transmission linkage? Or what else could it be?
Your guess is a good one. Yes, it can be a linkage problem.
An experienced mechanic will be able to check this idea out and properly adjust the linkage.
Linkage becomes slightly bent and / or loose. This prevents the clutch fully disengaging and allowing the shift out of or into gear.