Chrysler Full-Size Trucks 1967-1988 Repair Guide

Timing Gears

Print

REMOVAL & INSTALLATION



Diesel Engines

See Figures 1 and 2

To remove:
  1. Remove the timing gear cover, the gasket and the front seal.
  2.  
  3. Remove the idler pulley bracket.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Diesel timing case and gear system

  1. Align the timing marks.
  2.  
  3. Using a puller, remove the camshaft drive gear.
  4.  
  5. Turn the injection pump to allow the notch in the drive gear to pass by the idler gear teeth.
  6.  
  7. Loosen the idler gear mounting bolt. Remove the thrust plate and remove the idler gear.
  8.  
  9. Disconnect the injection lines at the pump.
  10.  
  11. Disconnect the fuel line at the transfer pump and cap all openings.
  12.  
  13. Disconnect the transfer pump-to-filter hose.
  14.  
  15. Disconnect the filter-to-injection pump hose.
  16.  
  17. Loosen the stay bolt on the back of the injection pump. Remove the pump, automatic timing gear and the flange, by pulling toward the back of the engine.
  18.  

To inspect:
  1. Inspect all parts for wear or damage. Replace any suspect parts.
  2.  
  3. Put the camshaft gear back on the shaft and check for shaft end-play with a dial indicator. End-play should be 0.001-0.008 in. (0.05-0.22mm). If end-play exceeds the limit of 0.01 in. (0.30mm), replace the thrust plate.
  4.  
  5. Check the idler gear and shaft to make sure that the oil passage is open.
  6.  
  7. Measure the inside diameter of the idler bushing and the outside diameter of the idler shaft. ID should be 1.574-1.575 in. (40.000-40.025mm). OD should be 1.572-1.573 in. (39.950-39.975mm). Idler shaft-to-bushing clearance should be 0.0009-0.0029 in. (0.025-0.075mm). If the clearance exceeds 0.003 in. (0.100mm), replace the bushing. Use bushing replacer tool MH-061228.
  8.  

To install:
  1. Be sure that the crankshaft is set with No. 1 cylinder at TDC.
  2.  
  3. Install the idler gear on the shaft so the marks on the camshaft drive gear match up with the marks on the idler gear.
  4.  



Click image to see an enlarged view

Fig. Fig. 2: Diesel timing gear alignment

  1. Install the thrust plate and the hold-down bolt. Torque the bolt to 25 ft. lbs. (34 Nm).
  2.  
  3. Install the camshaft gear and the thrust plate on the camshaft. Be sure all the marks line up with the marks on the idler gear. Tighten the hold-down bolt to 12 ft. lbs. (16 Nm).
  4.  
  5. Put the injection pump in position and mesh the pump drive gear with the idler gear so the marks on the drive gear match up properly with the marks on the idler gear. Be sure the pump mounting flange scale is set at the proper injection point.
  6.  
  7. Install the mounting nuts on the timing gear case and tighten them.
  8.  
  9. Connect the fuel feed line and the filter hoses to the pump.
  10.  
  11. Operate the primer pump to bleed the air from the fuel system.
  12.  
  13. Connect the injector pipes.
  14.  
  15. Check the idler gear for end-play using a feeler gauge between the gear and the thrust plate. It should be 0.001-0.005 in. (0.05-0.15mm). If it exceeds 0.013 in. (0.35mm), replace the thrust plate.
  16.  
  17. Check the gears for backlash by mounting a dial indicator so that lash is measured from the gear tooth profile at right angles to the gear shaft. When checking lash between the idler gear and injection pump drive gear, be sure that the stay bolt at the back of the pump is tight. Backlash should be 0.004-0.009 in. (0.11-0.24mm). If backlash exceeds 0.30mm, replace the gear.
  18.  
  19. Install a new front seal (using a new gasket), the timing gear cover and the crankshaft drive pulley.
  20.  
  21. Check the oil seal and cone surfaces. Runout should not exceed 0.01 in. (0.5mm). If it does, or if any contact surface is damaged, replace the pulley.
  22.  

 
label.common.footer.alt.autozoneLogo