Hyundai Repair: transmission, sonata 2, problem wit

Question
Hi I'm drivin a 2004 EF Sonata 2.4 n I'm some problem wit my gear box!d gear over revvs at 3rd gear when its going into 4th gear.and when I push d gear from P to other gears it takes a few seconds to change!can u give me some advice on wats actually happening...should I change d whole gear box o jz try to fix it??which is better and lasting??I need ur advice on this as soon as possible..thank you very much...I'm from Malaysia!!

Answer
This is most likely in the transmission, but you should definitely take the car in to be checked.  Presuming the same service procedures apply in Canada, there's a technical service bulletin (TSB) which describes how to determine whether the adaptive values need to be relearned, there's a problem with the transmission control module, there's a small problem with the transmission, or there's a large problem with the transmission.

In the event of a large transmission problem, your best bet is to replace the entire unit with a factory remanufactured transmission.