My daughter's 2000 Tiburon seemed to slip out of gear. The mechanic pulled a code stating incorrect gear ratio (4th). Does anyone know what part needs replacing?

 

Is this a manual or an automatic transmission? Which engine? It would also be helpful if you could remember the exact error code (e.g. P0720 or something like that) that the mechanic recovered with his scanner.

 

If it's a 2000 RD Tiburon it must be the 2.0L Beta 4-cyl engine. However, like Ken said, knowing if it's an auto or manualtranswould help.

Since you said 4th gear I assume the code is either:
P0730 Incorrect Gear Ratio
P0734 Gear 4 Incorrect ratio

Things to check:
a. Check the pulse generator A and B connector
b. Check the pulse generator A and B
c. Kickdown brake slippage
d. Check the end clutch or control system
e. Check the pulse generator wiring harness