In the Proton Exora, Preve, FLX models with CVT (Continuously Variable Transmission), the input shaft planetary system is a key part of the transmission’s mechanism. This system works together with the variator (pulley system) to provide smooth and continuous gear ratios. Understanding the function of the input shaft planetary system and how it fits into the CVT is crucial for diagnosing and repairing transmission issues.

What is the Input Shaft Planetary System in a CVT?

The input shaft planetary system is part of the planetary gear set, which plays a role in the overall power delivery and ratio control within the CVT. In a CVT transmission, instead of having fixed gear ratios like in traditional automatic gearboxes, the planetary gear system adjusts to provide an infinite range of gear ratios, ensuring smooth acceleration without the jarring shifts seen in other types of transmissions.

The planetary gear set in a CVT typically includes:

• Sun Gear: The central gear that is driven by the input shaft.
• Planet Gears: Multiple smaller gears that rotate around the sun gear.
• Ring Gear: The outer gear that meshes with the planet gears.
• Carrier: Holds the planet gears in place.

The planetary gear system in a CVT allows the input shaft to smoothly transfer engine power to the variator. This system can adjust the ratio continuously as the pulleys expand and contract, depending on driving conditions.

Role of the Input Shaft in the Planetary Gear System

The input shaft serves as the conduit for transferring power from the engine to the CVT's planetary gear set. Here’s how the input shaft works in a CVT transmission:

1. Power Transfer from Engine:

   • The input shaft connects to the engine's flywheel or torque converter, transferring the rotational power generated by the engine to the transmission’s planetary gear set.

2. Adjusting Gear Ratios:

   • The input shaft drives the sun gear, which then interacts with the planet gears and ring gear to adjust the transmission's output. In CVTs, this system continuously adjusts the gear ratio by shifting the size of the pulleys, ensuring smooth acceleration.

3. Torque Management:

   • The input shaft also helps manage the torque generated by the engine, ensuring that it is efficiently delivered to the wheels. This is crucial in a CVT, where the transmission needs to adjust the torque load based on the varying gear ratios.

Symptoms of a Faulty Input Shaft Planetary System

If there is an issue with the input shaft planetary system in the CVT, it can result in various performance issues. Common symptoms include:

1. Slipping Transmission:

   • A worn or damaged input shaft planetary system may cause the CVT to "slip," meaning the engine revs up without a corresponding increase in vehicle speed. This happens when the gear ratios are not adjusting correctly.

2. Erratic Shifting:

   • The vehicle may experience inconsistent or jerky acceleration as the planetary gears struggle to provide the proper torque and gear ratios.

3. Unusual Noises:

   • Grinding, whining, or clattering noises could indicate wear or damage in the planetary gears, input shaft, or related components. These noises are often associated with metal-to-metal contact in the gear system.

4. Loss of Power:

   • A failing input shaft planetary system can lead to a lack of power delivery to the wheels, making the car feel sluggish or unresponsive.

5. Fluid Leaks:

   • Transmission fluid leaks around the input shaft or planetary system can indicate seal or housing damage, leading to decreased hydraulic pressure in the system and poor transmission performance.

6. Warning Lights:

   • The Check Engine or Transmission Warning Light may illuminate, indicating an issue with the transmission's internal components. Diagnostic trouble codes (DTCs) may indicate problems with the input shaft planetary system or related sensors.

Diagnosing Input Shaft Planetary Issues

To diagnose issues with the input shaft planetary system, the following steps can help identify the source of the problem:

1. Diagnostic Trouble Codes (DTCs):

   • Use an OBD-II scanner to check for any fault codes related to the transmission. Codes such as P0730 (incorrect gear ratio) or P0740 (torque converter clutch solenoid circuit) could indicate input shaft or planetary system problems.

2. Fluid Pressure Testing:

   • A mechanic may test the hydraulic fluid pressure in the transmission to check if the input shaft planetary system is operating under correct pressure. Low fluid pressure can indicate internal leaks or component failure.

3. Physical Inspection:

   • If accessible, the input shaft and planetary gears can be visually inspected for signs of wear, rust, or damage. This may require removal of the transmission pan or disassembly of the transmission.

4. Listen for Noises:

   • Pay attention to any unusual sounds coming from the transmission. Grinding or whining could indicate damage to the planetary gears or the input shaft.

Replacing the Input Shaft Planetary System

If the input shaft planetary system is determined to be faulty, it may require disassembly of the transmission to replace the damaged components. Here is a general procedure for replacing the input shaft or planetary system in a CVT:

Tools and Parts Required:

• New or remanufactured input shaft planetary system (specific to Proton Exora, Preve, FLX models).
• Transmission fluid (Proton-approved CVT fluid).
• Gaskets and seals.
• Basic hand tools (socket set, torque wrench, screwdrivers).
• Transmission jack (for removing the transmission).
• Special tools for planetary gear assembly (if applicable).

Procedure:

1. Prepare the Vehicle:

   • Disconnect the vehicle’s battery to prevent electrical issues during the repair.
   • Raise the vehicle for transmission access.

2. Drain Transmission Fluid:

   • Drain the CVT fluid from the transmission to avoid spills when disassembling.

3. Remove the Transmission:

   • The transmission will likely need to be removed from the vehicle to access the input shaft planetary system. This step may involve removing the engine mounts and disconnecting drive shafts.

4. Disassemble the Transmission:

   • Remove the transmission pan and valve body. This will expose the planetary gear set, including the input shaft. Depending on the design, the planetary system may need to be fully removed to replace the input shaft.

5. Inspect and Replace Components:

   • Inspect the input shaft for wear or damage. If it is damaged, remove it and replace it with a new or remanufactured part. Also, check the planetary gears and replace them if necessary.

6. Reassemble the Transmission:

   • Reinstall all removed components, ensuring proper alignment and securing of bolts to the manufacturer’s torque specifications.

7. Refill Transmission Fluid:

   • Refill the CVT with the correct type of transmission fluid as specified by Proton.

8. Test and Program the Transmission:

   • After reassembly, test the vehicle to ensure proper operation. A diagnostic tool may be required to reset adaptive transmission settings and perform a transmission relearn procedure.

Preventive Maintenance for the Input Shaft Planetary System

To extend the life of the input shaft planetary system and prevent failure:

• Regular Fluid Changes:
  • Follow the manufacturer's recommendations for changing CVT fluid to keep the transmission running smoothly.
• Monitor Fluid Levels:
  • Ensure the transmission is properly filled with fluid and check for leaks around the input shaft or planetary system.
• Avoid Overloading:
  • Excessive loads or aggressive driving can put additional strain on the transmission, leading to premature failure of internal components like the input shaft and planetary gears.

Conclusion

The input shaft planetary system is a vital part of the CVT in the Proton Exora, Preve, FLX models. If this system is damaged, it can lead to a range of transmission problems, including slipping, erratic shifting, and loss of power. Diagnosing and replacing these components typically requires specialized knowledge and tools, as the transmission must be disassembled. Regular maintenance, including fluid changes and monitoring for leaks, can help prevent premature failure.

Let me know if you need more specific information or part numbers related to the input shaft planetary system for your CVT transmission!