Why can't I select 4th gear on peugeot boxer?

If you can't select 4th gear in your Peugeot Boxer, it may be due to several issues, such as a worn or damaged clutch, a problem with the gear linkage, or issues within the transmission itself. Low Transmission Fluid levels or contamination could also be causing shifting problems. It's advisable to have a professional mechanic inspect the vehicle to diagnose and resolve the issue accurately.