Replacing a planetary gear set in a BMW 735iL (or similar models) is a complex task that generally requires a good understanding of automotive mechanics, as well as specialized tools. click here for more details on the download manual…..
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Below is a detailed step-by-step guide to help you through the process. Note that this task can vary based on the specific model year and transmission type, so always consult the service manual for your specific vehicle.
### Components and Tools Needed
#### Components:
1. **Planetary Gear Set** – This is the actual assembly that you will be replacing.
2. **Transmission Fluid** – To refill the transmission after the replacement.
3. **Gaskets and Seals** – New gaskets and seals to prevent leaks after reassembly.
4. **Transmission Filter** – Recommended to change the filter when servicing the transmission.
#### Tools:
1. **Socket Set** – Metric sockets are essential (including deep sockets).
2. **Wrenches** – Metric wrenches for various bolts.
3. **Torque Wrench** – To ensure bolts are tightened to manufacturer specifications.
4. **Jack and Jack Stands** – To lift the vehicle safely.
5. **Transmission Jack** – To support and lower the transmission safely.
6. **Pliers** – For removing clips and other fasteners.
7. **Screwdrivers** – Both flat-head and Phillips.
8. **Magnetic Pickup Tool** – For retrieving dropped screws and small parts.
9. **Clean Rags** – To wipe surfaces and catch any spills.
### Step-by-Step Replacement Process
#### 1. Preparation
– **Disconnect the Battery**: Safety first. Disconnect the negative battery terminal to prevent any electrical issues.
– **Raise the Vehicle**: Use a jack to lift the vehicle and securely place it on jack stands.
#### 2. Remove the Transmission
– **Drain the Transmission Fluid**: Place a drain pan under the transmission and remove the drain plug to let the fluid drain completely.
– **Remove the Driveshaft**: If your model is rear-wheel drive, you’ll need to disconnect the driveshaft. Remove the bolts securing the driveshaft to the rear differential and slide it out.
– **Disconnect Transmission Linkages**: Remove any linkages connected to the transmission, including the shift linkage.
– **Unbolt Transmission Mounts**: Support the transmission with a transmission jack, then remove the bolts from the transmission mounts.
– **Disconnect Electrical Connections**: Unplug any electrical connectors associated with the transmission.
– **Remove the Transmission**: Carefully lower the transmission from the vehicle using the transmission jack.
#### 3. Disassemble the Transmission
– **Remove the Transmission Pan**: Once the transmission is on a workbench, remove the transmission pan bolts and carefully take off the pan. Be prepared for some residual fluid to spill out.
– **Remove the Filter**: Take out the transmission filter to access the internal components.
– **Remove Valve Body**: Unbolt and carefully lift out the valve body to expose the planetary gear set.
– **Identify the Planetary Gear Set**: The planetary gear set typically consists of the sun gear, ring gear, and planet gears.
#### 4. Replace the Planetary Gear Set
– **Remove the Old Planetary Gear Set**: Carefully unbolt any retaining rings or clips holding the planetary gear set in place. Remove the gears and set them aside.
– **Install the New Planetary Gear Set**: Place the new planetary gear set into the transmission housing, ensuring it is seated correctly. Reinstall any retaining clips or rings that hold it in place.
#### 5. Reassemble the Transmission
– **Reinstall the Valve Body**: Carefully position the valve body back into place
and secure it with bolts, ensuring all components are correctly aligned.
– **Install the New Filter**: Place the new transmission filter in its designated spot.
– **Reattach the Transmission Pan**: Clean the mating surfaces and install a new gasket for the transmission pan. Bolt it back into place.
#### 6. Reinstall the Transmission
– **Lift the Transmission Back into Place**: Using the transmission jack, carefully raise the transmission back under the vehicle. Align it with the engine and transmission mounts.
– **Secure the Transmission**: Bolt the transmission mounts back into place.
– **Reconnect Driveshaft and Linkages**: Reattach the driveshaft and any transmission linkages you previously removed.
– **Reconnect Electrical Connectors**: Plug back any electrical connections to the transmission.
#### 7. Fill the Transmission
– **Add New Fluid**: Using a funnel, add the appropriate type and amount of transmission fluid as specified in the owner’s manual.
– **Reconnect the Battery**: Reattach the negative battery terminal.
#### 8. Final Checks
– **Start the Vehicle**: Start the engine and let it warm up. Check for any fluid leaks around the transmission.
– **Test Drive**: Take the vehicle for a short test drive to ensure the transmission shifts properly.
### Conclusion
This process is intricate and requires mechanical skills, as well as attention to detail. Always refer to the BMW service manual for your specific model for torque specifications and any specific procedures related to your vehicle. If you are not confident in performing this task, it may be best to consult with a professional mechanic.
A valve shim is a crucial component found in the engine of many internal combustion vehicles, particularly those with overhead cam (OHC) designs. It serves as a precision spacer that adjusts the clearance, or “lash,” between the engine’s valve stem and the rocker arm or camshaft. The primary purpose of a valve shim is to maintain optimal valve operation, ensuring that the valves open and close at the correct timing and with the appropriate amount of lift. This is vital for the engine’s performance, efficiency, and longevity.
Valve shims are typically made from hardened steel or other durable materials to withstand the high temperatures and pressures present in an engine. they come in various thicknesses, allowing for precise adjustments based on the specific requirements of the engine’s valve train. Over time, as the engine components wear, the clearance between the valve stem and rocker arm can change, potentially leading to issues such as poor engine performance, increased emissions, or even engine damage.
To address this, mechanics may measure the valve clearances during routine maintenance and replace or adjust the shims as necessary. This process is often part of a larger service known as a valve adjustment. By ensuring that the valve shims are correctly set, the engine can operate more smoothly and efficiently, promoting better fuel economy and overall performance.