GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Flywheel

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On most of the engines covered by this guide the flywheel and the ring gear are machined from one piece of metal and cannot be separated. On some of the 4.3L engines the ring gear is a separate piece and can be driven from the flywheel once the gear is heated using a torch.

REMOVAL & INSTALLATION



See Figures 1 through 7



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Fig. Fig. 1: Installing the flywheel in the vehicle



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Fig. Fig. 2: View of the flywheel and related components (automatic transmission)



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Fig. Fig. 3: View of the flywheel and related components (manual transmission)

  1. Remove the transmission assembly from the vehicle.
  2.  
  3. If equipped with a manual transmission, remove the clutch and pressure plate assembly.
  4.  
  5. If equipped, remove the flywheel cover.
  6.  
  7. Remove the flywheel-to-crankshaft bolts, then remove the flywheel and spacer (if used) from the engine.
  8.  



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Fig. Fig. 4: If a flywheel holding tool is not available install one of the transmission retaining bolts, then use a crowbar to prevent the flywheel from turning while loosening its bolts



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Fig. Fig. 5: After all the bolts have been unfastened, remove the flywheel



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Fig. Fig. 6: Remove the spacer or clutch housing cover (if equipped)



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Fig. Fig. 7: Use a torque wrench to tighten the flywheel bolts to specification

To install:
  1. Inspect the flywheel for cracks, and inspect the ring gear for burrs or worn teeth. Replace the flywheel if any damage is apparent. Remove burrs with a mill file. Remove ant thread sealer from the flywheel bolts.
  2.  
  3. Install the spacer (if used) and the flywheel. Most flywheels will only attach to the crankshaft in one position, as the bolt holes are unevenly spaced and/or the crankshaft is fitted with a dowel pin.
  4.  
  5. On 1998-99 2.2L engines, apply Loctite® 271 or equivalent to the flywheel bolts. Follow the instructions supplied with the thread locking compound to ensure proper bolt retention. Install the bolts and tighten to 55 ft. lbs. (75 Nm) on 2.2L engines and 75 ft. lbs. (100 Nm) on 4.3L engines using a crisscross pattern.
  6.  
  7. If equipped, install the clutch and pressure plate assembly.
  8.  
  9. Install the transmission assembly.
  10.  

RING GEAR REPLACEMENT



  1. Remove the flywheel from the vehicle. Refer to the procedure outlined in this section.
  2.  
  3. Make certain that the ring gear is a separate piece, then using a torch, uniformly heat it around the entire circumference. DO NOT heat the gear until it is red hot as this will change the metal structure.
  4.  
  5. When the ring gear is hot enough, drive it off the flywheel using a hammer.
  6.  

To install:
  1. Using a torch, heat the ring gear uniformly until it expands enough to be installed on the flywheel.
  2.  


CAUTION
Never heat the ring gear to a temperature above 400ºF (204ºC) as this will weaken the structure of the metal.

  1. When the ring gear and flywheel have cooled sufficiently, install the flywheel on the vehicle.
  2.  

 
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