Here is a transmission comparison that I did a while back.
1. Manual Shift: plain old standard shift transmission. No synchronizers thus you have to stop and clutch for each gear change. You can’t shift on the go without grinding gears. Usually have 6-8 forward gears and 1-2 reverses.
2. Synchro-Shift: Basically the same as the manual shift except it has synchronizers and can be shifted on the go. The clutch should always be used for starts, stops as well as shifting. Usually has 6-8 forward gears and 1-2 reverses.
3. Shuttle-Shift or Synchro-Shuttle: This is a standard transmission that may have as many gears in reverse as forward. There is lever on the left of the steering that performs the forward to reverse gear change. Most Shuttle Shifts have some synchronized gears or they may be fully synchronized. The clutch must be used to start, stop and change directions. Usually has 9, 12 or 16 gears in each direction. May have a gear as low as ¼ MPH on the 16 speed models.
4. Power-Shuttle: With this Standard transmission, you can change forward to reverse directions and also start and stop without using the clutch. Most if not all Power Shuttle transmissions have fully synchronized gears. Usually has 9, 12 or 16 gears in each direction. May have a gear as low as ¼ MPH on the 16 speed models. (JD calls this a Power Reverser)
5. Power-Shift: This standard transmission has all of the benefits of the power shuttle as well as being able to shift between gears without the clutch. It can be started, stopped, changed from forward to reverse and the gears shifted without the clutch. Usually has 9, 12 or 16 gears in each direction. May have a gear as low as ¼ MPH on the 16 speed models. (Massey Ferguson’s DynaQPS is a powershift and Kubota’s GST is essentially a powershift.)
If I have accidentally made a mistake on any of these let me know. I caught a place or two where I swapped items and had to change them.
