I was having problems shifting to 4th gear. 3rd was also sloppy. Sometimes it would jump out of gear. The fix is replacing the shift lever seat. This is a $12 part and can be done in about one hour. After the job was done the shifter was smooth and positive as if it were new. I also replaced the shift lever bush, $5 part. It did not need it but I had the lever out and it is a plastic part that probably has limited life.
Nick
Nick