12 x 12 Synchronized Shuttle Shift (SSS)

[dknarnd]

Can anyone tell me how this transmission works? According to the web page you can shuttle between reverse and forward by clutching and moving a shuttle leaver. What I am wondering is how is this transmission set up, must be a range selector, how many gears per range. I am assuming it has a range selector and to shift between ranges you must stop. When shifting between forward gears do you have to clutch but not come to a stop.

 

[RickB]

Forward, neutral and reverse synchronized selected on left dash.
Gears 1234 H pattern synchronized selected on right dash.
Ranges L M H no synchros selected at left hand side.
Clutch for all shifts stop for range shifts, stop for direction changes if you have any regards for synchronizer life.

 

[burnetma]

On the TN models you should note that the clutch is a DRY CLUTCH (not in oil bath). All shifts are made using mechanical linkages.

The hydraulic reverser is a WET CLUTCH which will greatly (at least 2X) extend clutch life. Gear & range selection are made with mechanical linkages. Forward, neutral & reverse is made an electronic signal from the hand lever to a hydraulic actuator in the transmission. More to go wrong, but it is a simple design. The wet clutch makes a big difference when doing a lot of heavy loader work and in a hurry (examples: commercial stone or gravel loading, silage wagon loading, etc...). Much less important for most home or estate owners.

 

[RickB]

You should note that TN's have either wet or dry clutches depending on whether they are Power Shuttle or Synchro Shuttle models. All TN PTO clutches are dry.
Synchro Shuttle Shift (SSS) nomenclature is found on some Ford and NH 20 series compacts and NH TC's, and operates as I described.
Electro-Hydraiulic Shuttle Shift (EHSS) is found on many Ford/NH 2120's and TC55's and is a true hydraulic reverser as the TN PowerShuttle.

 

[gregNH]

Is this transmission a good choose for mowing (+- straight lines==> not much direction changes and is this bad for my clutch if i change direction on high rpm with my pto at 540 BUT it are only a few changes (i think +- 20 times on +- 60 minutes), also a bit of gardening and hay making)

 

[JerryG]

Reducing RPM is better for any system with any type of clutch before shifting. The RPMs can be left at high speed, but it will wear more on any type of clutch.

 

[have_blue]

Hi Greg,

Theoretically, clutching at high speed will indeed wear the clutch faster. However, I don't think you will use the clutch very much when mowing. I guess I do 90% or my mowing turns without clutching. I set my throttle and gears to a comfortable speed and make fairly wide turns.

Extended FEL work is probably the worst activity for clutch wear. You really give the clutch a workout. That's why I use the lowest RPM I can use efficiently when doing FEL work. Using high RPM for FEL work snaps my neck uncomfortably anyway.

 

[gregNH]

today my dealer said that the sychro reverser wears fast when you changes direction when you where riding, so first make a complete stop.
BTW: i've decided to take a boomer with a manual transmission. I drove with it and it was perfect.

 

[have_blue]

I think your dealer is right. You can really feel the synchro working when you downshift. If you are used to a non-synchro transmission, you have probably developed the habit of stopping dead before shifting or changing directions.

Some guys have reported they run 2000 RPM or higher doing FEL work. I shudder at the thought of the clutch wear. This is 1 area where the HST really shines, but I still prefer the 12x12 for all around use and reliability.