As a start you should check your cable linkages of the shifting mechanism. There are two cables running into a plastic box in front of the gear box. Open the plastic cover of it and you will see the two ball joints of the shifting rods. Check if there is abnormal wear and tear at the end of the cables. It`s also a good idea to check for oil leaks and check the oil level of the transmission. The fill and drain plugs are inside of that plastic box to the left of the cable shifting mechanism. Marked in red you can see the drain plug which has magnet on it and in yellow the fill plug. Next to them are the the shifting cables, which you have to check. http://www.focusfanatics.com/forum/attachment.php?attachmentid=13820&stc=1&thumb=1&d=1199589273 If the cable linkages are all right you can try changing the transmission oil. Use good grade 75W-80. Cheers!