[thstone]

Start with a trans fluid change. Its cheap and easy.

Same for checking the shifter cables and motor/transmission mounts. All of those are easier and cheaper to replace than removing the transmission.

However, at the end of the day it might be a synchro going bad and the only fix is to repair or replace the trans. Depending on the type (5 spd or 6 spd), it can be cheaper to buy a used transmission, change the oil, and install rather than paying to have your trans opened up and repaired.