I have 1981 John Deere 4640 with 8 Power shift gears. My problem is that it moves a lot, especially from 7th to 8th. Even depressing the clutch pedal will give the tractor a hard shake. It’s even worse if you drop from 8th to 7th. Some other gears are a bit rough, but I was told this is normal for an 8 speed gearshift. Any ideas?
Both of my 4640s go sharply from 7 to 8. I usually do around 1700rpm on 7, then hit the clutch throttle up to 1,200 shifts to 8 and then let go of the clutch much, much smoother. Release the throttle, depress the clutch, then shift from 8 to 7. It’s much smoother again. I don’t know if this is the right way to “fix” it, but it has been working for 20 years.