The flywheel and flywheel housing are critical for the smooth operation of the Detroit Diesel Series 71 engine. The flywheel stores rotational energy and provides inertia to help maintain engine momentum, while the flywheel housing encloses and protects the flywheel assembly. Proper disassembly of these components is important during engine overhauls, clutch replacements, or other major maintenance procedures.

---

---

Safety Precautions:

• Disconnect the Battery: Always disconnect the battery before working on the flywheel to avoid accidental engine cranking or electrical shorts.
• Ensure the Engine is Cool: Allow the engine to fully cool before starting the disassembly process to avoid burns from hot components.
• Use Proper Lifting Equipment: The flywheel is heavy, and improper lifting can lead to injury or damage to the flywheel. Always use a hoist or lifting device to remove it safely.
• Wear Protective Gear: Use gloves and safety goggles when working on the flywheel and housing to protect yourself from debris or sharp edges.

---

Disassembly Steps Of Flywheel & Flywheel Housing For  71 Series Inline Engines (271, 371, 471, 671)

---

1. Remove the Transmission (If Necessary)

---

Before accessing the flywheel and flywheel housing, you may need to remove the transmission if it’s connected to the flywheel.

---

• Disconnect Transmission Components:
  • Depending on your setup, the transmission must be disconnected from the engine. This involves removing bolts and disconnecting the driveshaft, clutch, and transmission housing from the engine.
  • Use a transmission jack or hoist to carefully lower the transmission away from the engine and place it in a safe area.
    

    ---

2. Remove the Starter Motor

---

The starter motor is typically mounted near the flywheel housing. Removing the starter motor provides clear access to the flywheel.

---

• Disconnect the Electrical Connections:
  • Use a wrench to remove the positive and negative electrical connections from the starter motor. Label the wires to ensure proper reinstallation.
    

    ---

• Remove the Starter Motor Mounting Bolts:
  • Use a socket wrench to remove the bolts securing the starter motor to the engine block. Once the bolts are removed, carefully lift the starter motor away from the flywheel housing and set it aside for inspection.
    

    ---

3. Remove the Flywheel Housing Cover

---

The flywheel is enclosed in the flywheel housing. Removing the cover allows you to access the flywheel for disassembly.

---

• Loosen the Flywheel Housing Bolts:
  • Use a socket wrench to loosen and remove the bolts securing the flywheel housing cover. Be sure to keep the bolts organized for reassembly.
    

    ---

• Remove the Flywheel Housing Cover:
  • Carefully lift the flywheel housing cover away from the engine. If it is stuck due to old gaskets or sealant, gently tap it free with a rubber mallet. Avoid prying with metal tools that could damage the cover or engine block.
    

    ---

4. Lock the Flywheel in Place

---

Before removing the flywheel, it is important to lock it in place to prevent it from rotating while you loosen the mounting bolts.

---

• Use a Flywheel Locking Tool:
  • Insert a flywheel locking tool or wedge a screwdriver between the teeth of the flywheel and the housing to prevent the flywheel from moving.
    

    ---

5. Loosen and Remove the Flywheel Bolts

---

The flywheel is bolted to the engine crankshaft. These bolts need to be removed carefully, as the flywheel is heavy and can drop suddenly.

---

• Loosen the Flywheel Bolts:
  • Use a socket wrench or breaker bar to loosen the flywheel mounting bolts. Loosen them gradually in a criss-cross pattern to evenly release pressure on the flywheel.
    

    ---

• Remove the Flywheel:
  • Once the bolts are loosened, use a hoist or another lifting device to support the flywheel as you remove the last few bolts. Carefully lower the flywheel from the engine and place it in a safe location for inspection.
    

    ---

6. Inspect the Flywheel and Housing

---

With the flywheel removed, thoroughly inspect the flywheel, ring gear, and housing for wear or damage.

---

• Inspect the Flywheel:
  • Check the flywheel surface for signs of cracks, warping, or excessive wear. Look for heat spots or scoring on the flywheel’s surface, which can indicate clutch or transmission problems.
    

    ---

• Inspect the Ring Gear:
  • Inspect the ring gear teeth for wear or damage. Worn teeth can prevent proper engagement with the starter motor and should be replaced if necessary.
    

    ---

• Inspect the Flywheel Housing:
  • Check the flywheel housing for cracks or signs of oil leaks. If the housing is damaged, it may need to be replaced.

---

Reassembly Notes:

---

1. Inspect and Resurface the Flywheel (If Necessary):
   • If the flywheel surface is warped, cracked, or heavily scored, it may need to be resurfaced or replaced. Always ensure the flywheel is flat and free of defects before reinstallation.
     

     ---

2. Reinstall the Flywheel:
   • Use a hoist or lifting device to position the flywheel back onto the engine crankshaft. Align the bolt holes and insert the flywheel bolts.
     

     ---

   • Torque the Flywheel Bolts: Tighten the flywheel bolts evenly in a criss-cross pattern to the manufacturer’s specified torque settings. Over- or under-tightening can cause flywheel misalignment or damage.
     

     ---

3. Reinstall the Flywheel Housing Cover:
   • After the flywheel is secured, reinstall the flywheel housing cover. Ensure that the gasket or sealant is in good condition to prevent oil leaks. Tighten the bolts evenly.
     

     ---

4. Reinstall the Starter Motor:
   • Reinstall the starter motor by aligning it with the mounting points on the engine block. Tighten the mounting bolts and reconnect the electrical connections.
     

     ---

5. Reinstall the Transmission (If Removed):
   • If the transmission was removed, reinstall it by aligning the transmission housing with the flywheel. Secure the transmission with the appropriate bolts and reconnect the driveshaft and clutch components.

---

Inspection Tips:

---

• Check for Flywheel Runout:
  • After reinstalling the flywheel, check for excessive runout using a dial indicator. Excessive runout can indicate a warped flywheel or misalignment, which can cause vibration or clutch issues.
    

    ---

• Check the Ring Gear:
  • Ensure that the ring gear is properly aligned and that the teeth are in good condition. Worn teeth can prevent proper engagement with the starter motor, causing starting issues.
    

    ---

• Inspect for Oil Leaks:
  • Check the area around the flywheel housing for any signs of oil leaks after reassembly. If oil leaks are present, replace the gasket or seal to ensure proper sealing.