Just making sure, you said to tighten up the rods going from 3rd to 4th.
Or, did you mean (because it's 3rd gear I have a problem sometime getting it in to) the 2nd to 3rd rods ?
Remove the nut that holds the 3/4 lever on the trans cover. Pull the lever off the stud, give it two turns clockwise to shorten the rod length, reinstall, test.
I recently had a little trouble with mine going into 4th. In my case I lengthened the 3/4 rod two turns to correct it. Fixed.
