Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSINFINITI2008FX45 AWD V8-4.5L (VK45DE)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTTRANSMISSION CONTROL SYSTEMSDESCRIPTION AND OPERATIONA/T CONTROL SYSTEMSHIFT MECHANISM
2008 Infiniti FX45 AWD V8-4.5L (VK45DE)
Shift Mechanism
2008 Infiniti FX45 AWD V8-4.5L (VK45DE)SECTION Shift Mechanism
Shift Mechanism
The A/T uses compact triple planetary gear systems to improve power transmission efficiency, simplify construction and reduce weight. It also employs an optimum shift control and super wide gear ratios. They improve starting performance and acceleration during medium and high-speed operation.
CONSTRUCTION
FUNCTION OF CLUTCH AND BRAKE
CLUTCH AND BAND CHART
POWER TRANSMISSION
"N" Position
Since both the forward brake and the reverse brakes are released, torque from the input shaft drive is not transmitted to the output shaft.
"P" Position
The same as for the "N" position, both the forward brake and the reverse brake are released, so torque from the input shaft drive is not transmitted to the output shaft. The parking pawl linked with the selector lever meshes with the parking gear and fastens the output shaft mechanically.
"D1" Position
The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear. The 1st one-way clutch regulates reverse rotation of the rear sun gear. The 3rd one-way clutch regulates reverse rotation of the front sun gear. During deceleration, the mid sun gear turns forward, so the forward one-way clutch idles and the engine brake is not activated.
"M1" Position
^ The front brake fastens the front sun gear.
^ The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.
^ High and low reverse clutch connects the rear sun gear and the mid sun gear.
^ The low coast brake fastens the mid sun gear.
^ During deceleration, the low coast brake regulates forward rotation of the mid sun gear and the engine brake functions.
"D2" Position
^ The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear. The 3rd one-way clutch regulates reverse rotation of the front sun gear.
^ The direct clutch is coupled, and the rear carrier and rear sun gear are connected. During deceleration, the mid sun gear turns forward, so the forward one-way clutch idles and engine brake is not activated.
"M2" Position
^ The front brake fastens the front sun gear.
^ The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.
^ The direct clutch is coupled, and the rear carrier and rear sun gear are connected.
^ The low coast brake fastens the mid sun gear.
^ During deceleration, the low coast brake regulates forward rotation of the mid sun gear and the engine brake functions.
"D3" and "M3" Positions
^ The front brake fastens the front sun gear.
^ The direct clutch is coupled, and the rear carrier and rear sun gear are connected.
^ The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.
"D4" and "M4" Positions
^ The direct clutch is coupled, and the rear carrier and rear sun gear are connected.
^ The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.
^ The input clutch is coupled, and the front internal gear and mid internal gear are connected.
^ The drive power is conveyed to the front internal gear, mid internal gear, and rear carrier and the three planetary gears rotate forward as one unit.
"D5" and "M5" Positions
^ The front brake fastens the front sun gear.
^ The input clutch is coupled, and the front internal gear and mid internal gear are connected.
^ The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.
"R" Position
^ The front brake fastens the front sun gear.
^ The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.
^ The reverse brake fastens the rear carrier.
The A/T uses compact triple planetary gear systems to improve power transmission efficiency, simplify construction and reduce weight. It also employs an optimum shift control and super wide gear ratios. They improve starting performance and acceleration during medium and high-speed operation.
CONSTRUCTION
FUNCTION OF CLUTCH AND BRAKE
CLUTCH AND BAND CHART
POWER TRANSMISSION
"N" Position
Since both the forward brake and the reverse brakes are released, torque from the input shaft drive is not transmitted to the output shaft.
"P" Position
The same as for the "N" position, both the forward brake and the reverse brake are released, so torque from the input shaft drive is not transmitted to the output shaft. The parking pawl linked with the selector lever meshes with the parking gear and fastens the output shaft mechanically.
"D1" Position
The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear. The 1st one-way clutch regulates reverse rotation of the rear sun gear. The 3rd one-way clutch regulates reverse rotation of the front sun gear. During deceleration, the mid sun gear turns forward, so the forward one-way clutch idles and the engine brake is not activated.
"M1" Position
^ The front brake fastens the front sun gear.
^ The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.
^ High and low reverse clutch connects the rear sun gear and the mid sun gear.
^ The low coast brake fastens the mid sun gear.
^ During deceleration, the low coast brake regulates forward rotation of the mid sun gear and the engine brake functions.
"D2" Position
^ The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear. The 3rd one-way clutch regulates reverse rotation of the front sun gear.
^ The direct clutch is coupled, and the rear carrier and rear sun gear are connected. During deceleration, the mid sun gear turns forward, so the forward one-way clutch idles and engine brake is not activated.
"M2" Position
^ The front brake fastens the front sun gear.
^ The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.
^ The direct clutch is coupled, and the rear carrier and rear sun gear are connected.
^ The low coast brake fastens the mid sun gear.
^ During deceleration, the low coast brake regulates forward rotation of the mid sun gear and the engine brake functions.
"D3" and "M3" Positions
^ The front brake fastens the front sun gear.
^ The direct clutch is coupled, and the rear carrier and rear sun gear are connected.
^ The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.
"D4" and "M4" Positions
^ The direct clutch is coupled, and the rear carrier and rear sun gear are connected.
^ The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.
^ The input clutch is coupled, and the front internal gear and mid internal gear are connected.
^ The drive power is conveyed to the front internal gear, mid internal gear, and rear carrier and the three planetary gears rotate forward as one unit.
"D5" and "M5" Positions
^ The front brake fastens the front sun gear.
^ The input clutch is coupled, and the front internal gear and mid internal gear are connected.
^ The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.
"R" Position
^ The front brake fastens the front sun gear.
^ The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.
^ The reverse brake fastens the rear carrier.
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.