When you’re shifting from one particular gear the transmission produces noise.
Noise that is noticeable when shifting in one particular gear is an indication of gear related problem. Usually this kind of problem is cause by either a worn out gear or a worn bearing. Now, how to determine which of the two is the culprit?
One way of checking which of the two is causing the noise while shifting is to drive the car in an incline road in a gear position where the noise is heard, if the noise is much worst in an inclined road then the problem is a worn bearing, however if the noise is the same or less than the noise while driving on a flat road, this indicates a problem on the gear, specifically the gear teeth is badly worn.
Possible Cause of Transmission Problem
Worn bearing or worn gear teeth inside the transmission.
All about car Recommendation
With this kind of problem you do not have any option but to bring the car to a reputable auto repair shop that specialized in manual transmission and ask the mechanic to inspect the problem parts. Transmission is very complex that is why it is very difficult to determine the real problem without examining the actual parts. A qualified mechanic must open the transmission to determine the exact cause of the problem, with this kind of work expect an expensive payment to fix the problem.