GM Full-Size Trucks 1988-1998 Repair Information

Timing Gears

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REMOVAL & INSTALLATION



4.8L Engines

See Figure 1

The camshaft on these engines is gear driven, unlike the chain driven V6 and V8 engines. The camshaft must be removed to replace the gear.

  1. Disconnect the negative battery cable. Remove the camshaft and place in an arbor press.
  2.  

Support the camshaft gear not the thrust plate.

  1. Press the gear off of the camshaft and remove the thrust plate and the spacer.
  2.  

To install:
  1. Support the camshaft at the front journal with tool J-22912-01 or equivalent, and mount the camshaft in a press.
  2.  



Click image to see an enlarged view

Fig. Fig. 1: Timing gear alignment-4.8L engines

  1. Lubricate the thrust plate with engine oil.
  2.  
  3. Install the key if removed.
  4.  
  5. Install the spacer making sure the chamfer in the spacer faces toward the journal radius.
  6.  
  7. Install the thrust plate.
  8.  
  9. Install the camshaft gear on with the timing mark to the outside and press the gear on until it bottoms on the spacer.
  10.  
  11. Remove the camshaft from the press.
  12.  

The clearance between the camshaft and thrust plate should be 0.003-0.008 in.

 
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