Twin Clutch SST (Sport- or Sportronic Shift Transmission) is the brand name of a six-speed dual-clutch automatic transmission, developed by Getrag for Mitsubishi Motors. SST Transmission Getrag DCT470 (SST) Transmission Specialists! Kozmic Motorsports is the world’s leader for Getrag DCT470 performance upgrades, diagnostics, and repair.

• Deere’s SST transmission is unique in that it has DIFFERENTIAL LOCK and thus spin both wheels at the same speed for a truly straight line mow (if so desired). Other ZTRs do not have this feature. Differential lock is usually associated with high end tractors; the next Deere that has this features is.
• How to change your sst transmission fluid,forgot to tell you once you're done you need to start the car and shift through all the gears a few times.
• SST performance is the best transmission shop around. Reverse on my 2003 Honda Accord was not working. After a diagnostic scan showed the problem to be possibly transmission solenoids, I sought the help of the Honda dealership in Scranton and many other garages and transmission shops, but they all told me my transmission was gone and would need to be rebuilt or replaced.

A reverse engineered operator’smanual for computer geeks.
Preface: I’m a mechanicalengineer by education, a computer automation engineer byspecialization, and a embedded software programmer by practice. Ithink everything should be electronically controlled, and often(sometimes incorrectly) try to fit everything into a purposefuldesign.

What is a John Deere SST16?
Itis a revolutionary lawn tractor which John Deere began manufacturingin 2001.
It is classified as a Zero Turn Radius mower, although itcomes in the “package” or “form-factor”similar to that of a traditional tractor. However, looks aredeceiving in this case.

If you are an engineer, tech geek, oreven a gear head, you can probably appreciate some of the articles onawards that the SST has won. Very interesting reading, IMHO (in myhumble opinion). Just a very well designedtractor!
http://www.deere.com/en_US/spinsteer/awardwinningdesign.html

Traditional Rear Drive,Front Steer Tractors

The type of tractors that most peoplehave are rear wheel drive and steer with the front wheels. Thetechnical name for this type of steering control is “AckermannSteering” (see pic below). This effectively the type ofsteering used in automobiles. With automatic transmissions, thesetractors have a single rear hydrostatic transmission anddifferential that drives both rear wheels.

What makes a ZTR so special?

Most of the ZTRs on the market havetwo separate hydrostatic transmissions controlled independently bytwo levers. The left lever controls the left hydrostatictransmission, and the right lever controls the right hydrostatictransmission. If you’ve played the Atari arcade game called“Battlezone”, the controls are like that.

Normal ZTRs are usually rear engineand rear wheel drive, with front caster wheels (like on ashopping cart’s front wheels.) There are variations that have asingle joystick control, although these are less popular andtypically harder to operate.

The unique feature of a ZTR is afeature called counter-rotation steering. This feature allowsthe two rear wheels to rotate in opposite directions and thus quicklyspinning the mower around without moving forward or backwards. Thisis useful for maneuvering in tight spots.

Another feature of a ZTR is theability to turn with just one rear wheel rotating. Thistechnique is very useful if you mow in the same way a person with awalk-behind mower would, ie. with each consecutive swath in theopposite direction of the last with a bit of overlap. A single wheelrotation allows the mower to like up perfectly for the next pass.

Normalsteering with a ZTR is technically referred to as “differentialsteering”. The two rear wheels turn at different speedswhich causes to mower to turn towards the side in which the wheel isspinner slower. So, if you want to turn right, you make the leftwheel turn faster than the right wheel!

When you first get in and drive aSST, it looks like a traditional tractor and you instinctively expectit to behave like one. The problem is that it doesn’t behavelike a normal (Ackermann) steered tractor. You don’t haveany tactile feedback on the steering-wheel of the SST (or any ZTR forthat matter). People are so used to diving cars that if you put thembehind a vehicle with steering wheel and an accelerator, they expectthe vehicle to “feel” like a car. The SST doesn’tfeel this way and there may be some discomfort or awkwardness whenyou first ride it. For instance, turning the steering-wheel when thetractor was stopped, I expecting the front end to “crawl”a little bit from the rotation of the front tires; it doesn't.Turning the steering-wheel does not turn the front tires at all(unless the tractor is moving).

On the other hand, although the SSTis truly a ZTR mower, it also doesn’t feel like atraditional ZTR either. If you are use to normal ZTRs, the SSTmay feel doubly awkward because the first time you drive one, it mayalso feel like you simply cannot control the SST the way you wouldlike. (Doubly awkward because it also doesn’t feel like anormal “Ackermann” steered tractor.).

Don't lose hope. This is marveloustractor to drive. The SST is really a hybrid of the two, and itscontrols are somewhat different and quite unique. Understandinghow it operates will give you a much better appreciation of themower.

The main controls of the SST consistof a steering wheel and two foot pedals on the right side.

The two pedal are a standardaccelerator (gas pedal) and a separate reverse pedal (effectively agas pedal that drives in reverse.) The Steering wheel looks like anormal steering wheel except it is really a spring loaded controller(somewhat similar to the steering wheel controllers of a computer orgame console.) When the steering wheel is released, the internalsprings in the mechanism bring the wheel back to center. Sooutwardly, it looks very similar to the controls of a car.

Let’s start with the basics.Pressing the accelerator pedal down moves the tractor forward.Pressing the reverse pedal down moves the tractor backwards. Deere’sSST transmission is unique in that it has DIFFERENTIAL LOCKand thus spin both wheels at the same speed for a trulystraight line mow (if so desired). Other ZTRs do not have thisfeature. Differential lock is usually associated with high endtractors; the next Deere that has this features is the X465 2WS at$8700 retail.

The hardest thing to explain in termsof operation of the SST is probably the control of the steeringwheel. It's simple enough that anyone can get it and drive, butdifferent enough that it takes some time to fully understand thedifferences with a normal tractor. If I have to sum it up in onesentence, it would be “the slower you are moving forward, thetighter the turn”. However, that really would not explainthe operation in enough detail.

The way the SST turns is dependent onboth the steering wheel, the accelerator pedal and the currentforward speed of the tractor. This may be the hardest thing tounderstand or to “get a feel for” in terms of theoperation.

For computer geeks, I think it’seasiest to think of the pedal as having 4 distinct “interaction”zones with the steering:

1. Rest/Off Zone, ie. foot is off the pedal, no accelerating

2. Counter Rotate Zone, the accelerator is pressed down just a very small bit

3. Single Wheel Rotate Zone, accelerator is pressed down lightly

4. Differential Steer Zone, the speed is linearly variable and the steering is also linearly variable in this zone.

These zones are not distinct ordiscrete. They are continuous and the transition from one zone to thenext is gradual and smooth.

Let me explain each zone and how itinteracts with the steering:

1.Rest/Off Zone ( 0-2% accelerator )

• ACCELERATOR PEDAL: foot is off the pedal, no accelerating. (approx 0-2% of pedal)

• STEERING WHEEL: Steering had absolutely no effect.

• FORWARD MOTION: Vehicle does not move, does not even budge in response to the steering wheel.

2.Counter Rotate Zone

• ACCELERATOR PEDAL: just touch the pedal so it’s not in the Rest/Off Zone (approx 2-5%)

• STEERING WHEEL: tuning the steering wheel full left or full right will command the SST to counter-rotate steer.

• FORWARD MOTION: must be stopped or moving very slowly

• useful for maneuvering in tight spots.

3.Single Wheel Rotate Zone

• ACCELERATOR PEDAL: slightly depressed (approx 5 to 10%)

• STEERING WHEEL: turning the steering wheel left or right will rotate the mower by turning the appropriate rear tire and keep the other rear tire (near) motionless.

• FORWARD MOTION: stopped or slow speeds (the faster the tractor is going, the more the drivers needs to turn the steering wheel)

• this is probably the most frequent mode of turning, especially for mowing in swaths because the rotation puts your mower into the correct potion with a bit of overlap from the previously cut swath.

• A single wheel turn has the highest probability of tearing up the lawn. The wheel that is not turning will do the damage. Use a very slight counter-rotate or differential steer for this maneuver if you have problems with turf tearing.

4.Differential Steer Zone

• ACCELERATOR PEDAL: moderate to fully pressed. Position is proportional to speed. (approx 10 to 100%)

• STEERING WHEEL: proportional to radius of turn

• FORWARD MOTION: slow to fast speeds

• Tractor behaves the closest to a normal tractor

• Used for gradual turns.

• It's about the combination of speed, steering, and accelerator.

Again, the beauty of the SST'scontrols is that anyone can get into an SST and operate it. Theinterface is intuitive for basic operation. But to fully appreciateeverything this tractor can do and to operate it like a pro may takesome time. The more you drive it, the more you will like driving itas you get a feel for how it works.

The hood for the engineslopes downward for better visibility.

Although this might not seemsignificant, it's extremely functional. It allows the operator to seeimmediately in front of the tractor. Much more so than with a normaltractor. It’s allowed me to see very small toys BEFORE I runover them and shred them to bits. Normally, small object would belost in the grass, so the visibility issue is quite significant forme.

Halogen Lights

I’ve never mowed in the dark (Iprefer sun burn over mosquitoes) , but perhaps I will one day.

Briggs & StrattonVanguard Commercial Grade Engine

Long life andquieter engine. Has a 2 year warranty for commercial use!
(Compared with a Briggs & Stratton Intek V-Twin that only has a90-day warranty for commercial use. )

Safeties

Engine will shut off if you get offthe seat while the PTO is engage (blade is turning) or if the mowerdoes not have the parking brake on.
The mower will not mow inreverse with the PTO engage unless you first pull up the PTO switchfrom the engaged position.
This puts the PTO switch into itsspring-loaded (temporary) position. Hold the switch in this positionand you can then mow in reverse.

Mower Deck Control

The cut height is controlled by aknob (which I like), and the whole deck can be lifted up using a footpedal and then locked in the up (cleaning) position using a sliderjust below the steering wheel.

Towing Attachments

I’ve towed a plug aeratorbehind the SST and it works wonderfully. This is considered a lawntractor so you can’t pull tillers or cultivators with it. Youcan get snow blades and chains for the winter!
Deere also has aFRONT MOWER OPTION for the SST which is a 44” mowingdeck that extends in front of the tractor.

Differential Lock &Power Steering

The combination is usually onlyavailable on very expensive, high end tractors.

John Deere Support

Service and parts very readilyavailable!

Consumer Reports, June2003:

“Most (ZTRs) steer via twolevers like the ones on the Cub Cadet Z-Force 44 and theAriens Zoom 1640 915035; you push one forward and pull theother back. While that sounds simple, turns with both models wereawkward compared with the steering-wheel-equipped John DeereSpin-Steer SST-16.”

Hills

Deeredoes not recommend using this mower on steep hills with a sideapproach. If you approach a steep hill head-on so you go directly upthe hill, then down the hill, you won’t have any problems.

If you try to go along the side of asteep hill such that the SST is slanted from the horizon and one reartire is higher than the other, this is the worst case situation forthe SST.

Normally, the differential locks onthe SST and it’s easy to drive in a straight line. When themower is on a hill, this presents a problem because it feels like therear differential isn’t locked and there is a tendency to turn,down the hill. After considering the physics of this problem, Ibelieve I understand what is happening.

This is a front engine mower and thushas some weight in the front. Combine that with caster wheels thatallows completely free motion for the front and this is where theproblems arise. The caster wheels have no ability to prevent thefront end from sliding down the hill. This is done completely by therear tires. If you look at the diagram above, the force of gravity“g” has a “normal” component “n”that is perpendicular to the ground, and a tangential component “h”that has a tendency to pull the front of the tractor down the hill.Normally on a flat lawn, to drive in a straight line I wouldn’thave to touch the steering wheel. However, when navigating a hillfrom the side, you will likely have to compensate using the steeringwheel, and if the slope is fairly steep, then you will need toslow down enough such that the differential steering will compensatefor the traction difference of the tires, and also the tendency forthe front end to turn down the hill due to weight. Adding more weightto rear counteracts the front (engine) weight and I believe that'show the “Traction Assist Kit” from Deere helps thisproblem. ie. Weight in front and behind the rear axle (and tires) arecloser balanced. The other way the Traction Assist Kit helps is thatit adds more weight on the rear tires for traction.

WARNING: This applies to all mowerthat I can think of....
DO NOT MOW ON SLOPES WHEN THE GRASS WET.AVOID SUDDEN CHANGES IN DIRECTION WHEN ON A SLOPE.

The bottom line is that this tractorwill mow on a grade. Unlike a flat lawn, you will have to steer it onthe hill if you approach it from the side, and you may also have toslow down a bit. The Traction Assist Kit helps a lot, especially ifthe operator is lighter in weight. I can do all of my yard withoutany problems and the worst slope I have is about 20'. I only have theoption of a side approach because the slope is against the side ofthe house, and it did take me a few tries to get the hang of steeringon a slope. Slowing down a bit helps a lot in some cases!

NEW: Regarding weight distribution.The weight of the mower is about 625 lbs. The engine is about 100lbs. If you consider the transmissions and the driver (150lbs) , theweight distribution might be close to 67% on the rear and 33% onthe front. There may be very good reasons for this design. ie.more capable to accept front attachments, less damage to the lawn,etc?

Also, if you add the bagger, thatwill add more weight to the rear and remove weight from the front. Somuch weight in fact that John Deere recommends adding weight to thefront. My point is that it's really not too far off from the weightdistribution of normal ZTRs as other people would claim.
It justcomes in a much nicer package!

CONSUMER REPORTS JUNE 2003 TRACTORRELIABILITY

John Deere support. Go to the websites of the manufacturers. Check out what they offer. Check out theonline information. With Deere, you can find attachment information,access online users' manuals, etc. I have personally called the Deere1-800 number on a few occasions and a lady (P.S.) that helped me wasextremely knowledgeable and detailed to my surprise. Plus I can finda Deere dealer just about anywhere to get parts. Also Deere'sdistribution network is such that they can get parts to their dealersin a couple of days (except for the traction assist kit which I'vebeen waiting about 4 weeks for now.)

Easy to get diagrams and parts onlinethrough http://jdparts.deere.com

Durable, reliable, commerical gradeequipment. 2 years warranty on the engine under commercial use. (1year on the rest of the mower under commercial use.) ( 2 yearwarranty for residential use.)
Look at the Consumer Reports RepairHistory. Deere is the most reliabile.

Resale. It's a highly recognized andvery reputable brand. You can find parts for Deere's products thatdate back a long time!

Much better looking!!!! The green andyellow is eye catching.

You wife can drive it, andshe'll want to drive it.( On second thought, maybe that's a bad thing. )

The SST is considered a lawn tractorand not just a mower because it can push front attachments and pullrear attachments. It does a wonderful job doing so. Not all ZTRs arecapable of this.

Differential Lock & PowerSteering.

Also, because this mower can becontrolled with one foot on the accelerator pedal and one hand onsteering wheel, it leaves the other hand free to wave to yourneighbors as they watch you ride your mower. Similarly, you could useyour free hand to sip a drink! Just sit back and relax while you mow!

Hey, that's gotta be worth somethin'!;)

Sst Transmission For Sale

Although I don't run heavy-dutyconstruction equipment for a living, I have had the opportunity tooperate other machines such as bulldozers, skid steers, exacavators,and backhoe loader.

My opinion is that this is awonderful tractor to own and operate. I thoroughly enjoydriving it and it does a fantastic job cutting grass.
It's one ofDeere's hidden gem's! I highly recommend it! It's such a pleasure todrive I wish my lawn would grow faster.

If you have questions or comments,please email me at:
( please remove the “-123-” and“-456-” below as they were inserted to prevent SPAM bots.)
sst@my-123-little-456-family.com

spinsteerspin steer spin-steer SST16 SST-16 SST15 SST-15 SST18 SST-18 SST 15SST 16 SST 18 John Deere Review Reviews Comparison Good Bad

We are proud to offer repair or upgrade services for your SST!

Silver Sport Transmission

The SST transmission is a first generation DCT from Getrag. Unfortunately, that means it comes with some common issues effecting reliability, which include:

• P184b Code (loss of even gears)
• Shift Fork Magnet Failure
• Not Repairable at the Dealership
• Oil Pump Lubrication Failure (ironic…)
• Torque Damper Spring Failure

The SST unit has the potential to be a very reliable transmission with the necessary updates and upgrades. Our Repair Service strives to eliminate the common problems to deliver a worry-free SST.

Stop the frustration of constant SST failures and have the proper service done through us the first time with a 14 month/unlimited miles warranty!

Gear Vendor Vs Sst Transmission For Mopars

This Repair / Upgrade Service Includes:

Sst Transmission Tunnel Hump

• Fully In-Car Tested
• Fully programmed / Teach-In performed using a Mitsubishi MUT-3 Programming Tool
• Upgraded clutches (Please select from the drop-down).
• Upgraded 2-4 Shift Fork Magnet Assembly
• Inspection of Oil Pump
• Inspection of Torque Damper
• Inspection of Gears / Gear Hubs / Gear Sleeve Assemblies
• Bearings if Needed
• Fork Pistons
• New Internal Sump Filter
• New External Line Filter
• 2 Neodymium Magnets
• Axle Seals

Sst Transmission Upgrade

During this repair, we disassemble the transmission in its entirety and clean every component. We do not just add the bare minimum parts for operation. Our in-car testing also ensures proper operation off the pallet with a true plug-and-play rebuild. For a fraction of what a new transmission costs, we can update all the common issues, giving you peace of mind.

** Our NEW 700HP (should be called an 800hp+!) clutch is now publicly available! It includes a 4340 Chromoly basket for extra strength and more friction material.

Sst Transmission Fluid

Watch the video:750HP EVO SST Dyno Pull