Series 50 – Section 1.10 Gear Case Cover

Section 1.10
Gear Case Cover

The gear case cover and gear case housing bolt together at the front of the engine to form a sealed compartment for the engine gear train. See Figure "Engine Gear Case and Cover" .‪

Figure 1. Engine Gear Case and Cover

The gear case cover also serves as a retainer for the crankshaft front oil seal. See Figure "Crankshaft Front Oil Seal" . ‪

Figure 2. Crankshaft Front Oil Seal

Several components that are mounted to the gear case cover include the water pump, accessory drive assembly, and fan support bracket. See Figure "Gear Case Cover-mounted Components" .‪

1. Coolant Inhibitor Element‪	5. Alternator (Coach)‪
2. Accessory Drive‪	6. Air Compressor Drive Adaptor‪
3. Front Pulley Support‪	7. Power Steering Pump‪
4. Oil Filter‪	8. Adaptorless Air Compressor‪

Figure 3. Gear Case Cover-mounted Components

The front engine support is bolted to the front of the gear case cover, directly behind the crankshaft pulley and vibration damper. See Figure "Typical Front Engine Support" .‪

Figure 4. Typical Front Engine Support

Several access covers are provided on the gear case cover for service of the engine without removing the gear case cover. Removal of the camshaft drive gear access cover will allow the removal of the camshaft drive gear-to-camshaft bolt for camshaft and/or cylinder head removal without removing the gear case cover. See Figure "Camshaft Drive Gear Access Cover" .‪

1. Bolt‪	3. Gasket‪
2. Access Cover/Oil Filler Assembly‪	4. Gear Case Cover‪

Figure 5. Camshaft Drive Gear Access Cover

The fan support bracket includes the access cover for the adjustable idler gear. See Figure "Fan Support Bracket for Truck Models" .‪

Figure 6. Fan Support Bracket for Truck Models

With the fan support bracket and the camshaft drive gear access cover removed, the gear lash between the adjustable idler gear and the camshaft drive gear can be measured and adjusted. Refer to "1.21.2.1 Check Engine Timing" .‪

On vehicles without power steering, an access cover is provided for inspection of the air compressor drive gear. See Figure "Air Compressor Drive Gear Access Cover" .‪

Figure 7. Air Compressor Drive Gear Access Cover

On some vehicles equipped with power steering, the power steering hydraulic pump is mounted to the gear case cover in the place of the access cover, and is driven by a short coupling that fits in the splined hole in the center of the air compressor drive gear. The pump is installed with a gasket.‪

Section 1.10.1
Repair or Replacement of Gear Case Cover

To determine if repair is possible or replacement is necessary perform the following procedure. See Figure "Flowchart for Repair or Replacement of Gear Case Cover" .‪

Figure 8. Flowchart for Repair or Replacement of Gear Case Cover

Section 1.10.2
Removal of Gear Case Cover

With the engine mounted on an overhaul stand. Remove the gear case cover as follows:‪

1. Drain the engine oil and remove the engine oil pan. Refer to "3.9.2 Cleaning and Removal of Oil Pan" .
2. Loosen the fan hub mounting bolts. Loosen the fan adjusting bolt. Back the adjuster off far enough to remove the drive belts. Remove the fan and fan hub assembly. Refer to "4.5.2 Cleaning and Removal of Engine Cooling Fan" .
3. Loosen the alternator mounting bolts. Remove the alternator drive belts, alternator, and mounting brackets (if so equipped). See Figure "Alternator and Related Parts" .
   

   Figure 9. Alternator and Related Parts

4. Loosen the air conditioner compressor and mounting brackets (if so equipped).
5. Remove the water pump assembly. Refer to "4.2.2 Draining and Removal of Water Pump" .
6. Remove the power steering pump (if so equipped).

   NOTICE:
   Damage to the internal components may result. The oil pan cannot be used to support the front of the engine in a vehicle, as its thermoplastic construction will not support the weight.‪

7. Remove the crankshaft pulley. Refer to "1.13.2 Removal and Cleaning Crankshaft Pulley" .

   Note: Do not hit the face of the damper to loosen it.

8. Remove the vibration damper. Refer to "1.12.2 Cleaning and Removal of Crankshaft Vibration Damper" .
9. Loosen and remove the four bolts securing the front engine mount to the gear case cover. Remove the front engine mount.
10. Loosen and remove the five bolts that secure the accessory drive assembly to the gear case cover.
11. Remove the accessory drive assembly by pulling it straight out of the gear case cover to avoid damaging the rubber O-ring. See Figure "Accessory Drive Assembly" .
    

    Figure 10. Accessory Drive Assembly

12. There are a total of 34 bolts that secure the gear case cover to the gear case. Bolts 17, 18, 19 and 20 were removed with the front engine mount. Bolts F1 through F5 were removed in a previous step; refer to step 11 Loosen and remove bolts 1 through 16, 21, 22. See Figure "Gear Case Cover Bolt Arrangement (Front)" .
    

    Figure 11. Gear Case Cover Bolt Arrangement (Front)

    1. Remove the SRS. Refer to "2.20.2 Removal of Synchronous Reference Sensor" . Loosen and remove the six bolts on the back of the gear case on the intake side of the engine located around the air compressor drive assembly. See Figure "Gear Case Cover Bolt Arrangement (Left Rear)" . Remove the air compressor drive assembly.
    

    Figure 12. Gear Case Cover Bolt Arrangement (Left Rear)

    2. Loosen and remove the bolts on the back of the gear case on the water pump (right) side of the engine. See Figure "Gear Case Cover Bolt Arrangement (Right Rear)" .
    

    Figure 13. Gear Case Cover Bolt Arrangement (Right Rear)

13. Support the gear case cover with a suitable lifting device, using the front engine lift bracket. See Figure "Engine Gear Case Cover Removal" .
    

    Figure 14. Engine Gear Case Cover Removal

    Note: There is a rubber O-ring installed between the center of the bull gear hub and the gear case cover. The ring may adhere to the cover when it is removed. Be sure the ring is not lost. See Figure "Bull Gear O-ring" .

    

    Figure 15. Bull Gear O-ring

14. Tap the gear case cover with a fiber mallet or plastic hammer to loosen it from the gear case. Remove the engine gear case cover.

Section 1.10.2.1
Inspection of Gear Case Cover

Inspect the gear case cover as follows:‪

1. Clean all of the old gasket sealer from the mating surfaces of the gear case and gear case cover.
2. Clean the gasket material from the mating surfaces of any components or access covers that were removed from the gear case cover, and the gear case cover itself.

   EYE INJURY ‪
   To avoid injury from flying debris when using compressed air, wear adequate eye protection (face shield or safety goggles) and do not exceed 276 kPa (40 psi) air pressure.‪

3. Clean all of the removed parts except the electrical components with clean fuel oil and dry with compressed air.

   Note: Any time the gear case cover is removed, the crankcase oil seal must be replaced. Install the new front oil seal after the gear case cover has been installed to the engine.

4. If necessary, remove the crankshaft front oil seal at this time. Refer to "1.8.2 Removal of Front and Rear Crankshaft Oil Seal" . Inspect the gear case cover for stress cracks or breaks in the casting. Repair or replace as necessary.
5. Inspect all O-rings for signs of dryness or splitting. Replace as necessary.

Section 1.10.3
Installation of Gear Case Cover

Perform the following steps for gear case installation:‪

Note: Gasket eliminator cures with the absence of air. The length of time between gear case cover installation and torquing of the bolts that secure the gear case cover to the gear case should be kept to a minimum.

1. Apply a continuous 1/16 in. bead of gasket eliminator PT-7276 (Loctite 51580) or equivalent to the mating surface of the gear case.
2. Install two guide studs, J 36107 , to the gear case. See Figure "Gear Case Cover Locating Dowels" .
   

   Figure 16. Gear Case Cover Locating Dowels

3. Support the gear case cover with a suitable lifting device, using the front engine lift bracket. Position the gear case cover on the guide studs and slide it forward. Index the two dowels in the gear case. See Figure "Gear Case Cover Locating Dowels" .
4. There are 34 bolts that secure the gear case cover to the gear case (including five for the fan support bracket). Install them as follows:

   NOTICE:
   With gasketless parts such as the gear case cover, the torque values and tightening sequences are critical to prevent parts warpage.‪

   1. Install the shorter bolts, No. 1 through 16, 21, 22, in various locations at the front of the gear case cover. Tighten them finger tight. See Figure "Gear Case Cover Bolt Torque Sequence (Front)" . Remove the guide studs when installing bolts 7 and 14.
   

   Figure 17. Gear Case Cover Bolt Torque Sequence (Front)

   2. Torque bolts 1 through 16, 21, 22, to 58-73 N·m (43-54 lb·ft).
   3. Install the front engine mount to the gear case cover. Install the four, longer, front engine mount-to-gear case cover bolts, finger tight.
   4. Torque bolts 17, 18, 19 and 20 to 160-200 N·m (118-148 lb·ft). See Figure "Gear Case Cover Bolt Torque Sequence (Front)" .
   5. Bolts F1 through F5 are fan support bracket bolts. Install the fan support bracket and torque bolts F1, F2 and F3 to 58-73 N·m (43-54 lb·ft). Torque bolts F4 and F5 to 160-200 N·m (118-148 lb·ft).
   6. Install the six bolts on the intake (left) side of the engine around the air compressor drive. Torque the bolts to 58-73 N·m (43-54 lb·ft), using the sequence. See Figure "Gear Case Cover Bolt Torque Sequence (Left Rear)" . Install the SRS to the gear case; refer to "2.20.3 Installation of Synchronous Reference Sensor" .
   

   Figure 18. Gear Case Cover Bolt Torque Sequence (Left Rear)

   7. Install the bolts on the exhaust (right) side of the engine. Torque the bolts to 58-73 N·m (43-54 lb·ft). See Figure "Gear Case Cover Bolt Torque Sequence (Right Rear)" .
   

   Figure 19. Gear Case Cover Bolt Torque Sequence (Right Rear)

5. Install a new crankshaft front oil seal. Refer to "1.8 Crankshaft Oil Seals" .
6. Install the accessory drive assembly to the gear case. Refer to "1.29.5 Installation of the Accessory Drive" . Torque the bolts to 30-38 N·m (22-28 lb·ft), using the sequence. See Figure "Accessory Drive Assembly Bolt Torque Sequence" .
   

   Figure 20. Accessory Drive Assembly Bolt Torque Sequence

7. Install the vibration damper to the crankshaft. Refer to "1.12.3 Installation of Crankshaft Vibration Damper" .
8. Install the crankshaft pulley to the end of the crankshaft. Refer to "1.13.3 Installation of Crankshaft Pulley" .
9. Torque the six pulley bolts to 182-210 N·m (134-155 lb·ft). Mark the first bolt and work in a clockwise direction.
10. Install the water pump assembly. Refer to "4.2.7 Installation of Water Pump" .
11. Install a new O-ring between the power steering pump cover and the gear case (if so equipped). Install the power steering pump cover to the gear case cover with the six bolts. Tighten the bolts progressively in a star-shaped pattern to draw the power steering pump in evenly. Torque the bolts to 30-38 N·m (22-28 lb·ft), using a star-shaped pattern.
12. Insert a new gasket between the camshaft drive gear access cover and the gear case cover. Install the camshaft drive gear access cover to the gear case cover. Torque the bolts to 30-38 N·m (22-28 lb·ft), using the tightening sequence. See Figure "Access Cover Bolt Torque Sequences" .
    

    Figure 21. Access Cover Bolt Torque Sequences

13. Install the air conditioner compressor and brackets. Install the air conditioner compressor drive belt.
14. Install the alternator and brackets. Install the alternator drive belts.
15. Adjust the alternator and air conditioner compressor drive belts to the specifications. Refer to "13.5.7 Drive Belts" .
16. Install the engine oil pan and fill the crankcase. Refer to "13.5.1 Lubricating Oil" .