Jeep CJ/Scrambler 1971-1986 Repair Guide

Dana/Spicer 20 Overhaul

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DISASSEMBLY



See Figure 1

  1. Remove the bottom cover from the case.
  2.  
  3. Remove the front drive shift bar poppet spring access hole plugs from the front output shaft bearing retainer. If it is necessary to remove the shift bar lock plungers, remove the 2 expansion plugs from the housing.
  4.  
  5. Remove the idler gear shaft lockplate bolt and lockplate.
  6.  
  7. Using a brass drift and hammer, drive out the idler gear shaft, driving from the front end of the case. As the shaft passes the thrust washers, remove the washers. Remove the idler gear and bearings with the spacers. Remove the bearings and spacers from the bore of the idler gear.
  8.  
  9. Remove the end yoke retaining lock nuts from the front and rear of the output shafts. Using a gear puller, remove the end yokes.
  10.  
  11. Remove the retaining springs from the shift levers. Remove the setscrew securing the shift lever pin. Remove the pin and left out each lever.
  12.  
  13. Remove the socket-headed screw from the underdrive shift fork.
  14.  
  15. Move the underdrive shift fork and rear output shaft sliding gear forward far enough for the gear to clear the splines on the rear output shaft. Swing the fork and gear toward the cover opening and lift them out.
  16.  
  17. Remove the rear output shaft bearing retainer and output shaft as an assembly.
  18.  
  19. Remove the front output shaft rear cover and shims. Tag the shims for assembly.
  20.  
  21. Remove the socket-headed setscrew from the front wheel drive shift fork.
  22.  
  23. Remove the front output shaft bearing retainer with the shift bars and gasket.
  24.  
  25. Pull forward on the front output shaft as far as possible to permit removal of the bearing cup. Remove the bearing cone from the front output shaft with a gear puller.
  26.  
  27. Remove the front output shaft bearing snapring. Using a plastic mallet, tap on the front end of the output shaft. Take out the driven gear and sliding gear along with the shift fork.
  28.  
  29. Remove the shift bars from the retainer.
  30.  


CAUTION
Be careful to secure the poppet balls and springs. The springs are under considerable tension and the ball and springs could fly out causing personal injury!

  1. Remove the shift bar oil seals.
  2.  
  3. Remove the speedometer driven gear.
  4.  
  5. Place the inner face of the bearing retainer in a press and press the output shaft from the retainer.
  6.  
  7. Remove the oil seal from the retainer bore.
  8.  
  9. Remove the tapered bearing cone and cup from the rear bore of the retainer. Remove the tapered bearing cup from the front bore. Remove the O-ring.
  10.  
  11. Using a gear puller, remove the bearing cone from the output shaft. Remove the shims from the shaft and tag them for installation.
  12.  
  13. Remove the speedometer drive gear.
  14.  
  15. Using a gear puller, remove the bearing cone from the front output shaft.
  16.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the Dana 20 transfer case

ASSEMBLY



  1. Press the bearing cone on the front output shaft.
  2.  
  3. Install the speedometer drive gear.
  4.  
  5. Install the bearing cone and shims on the output shaft.
  6.  
  7. Install the O-ring and tapered bearing cup in the front bore. Install the tapered bearing cone and cup in the rear bore of the retainer.
  8.  
  9. Install the oil seal in the retainer bore.
  10.  
  11. Place the rear output shaft into the retainer and support the shaft in a press. Using an adapter slightly larger than the shaft, press the bearing cone onto the shaft. Locate the rear output shaft bearing retainer in a fixed position. Set up a dial indicator and check the shaft endplay. End-play should be 0.003-0.005 in. (0.08-0.13mm). Add or remove shims to adjust. End-play is critical.
  12.  
  13. Install the speedometer driven gear.
  14.  
  15. Install the shift bar oil seals.
  16.  
  17. Install the poppet springs and balls. The heavier spring if for the front shift bar.
  18.  
  19. Depress the balls and install the shift bars in the retainer. Make sure that the seal lips are not damaged.
  20.  
  21. Install the driven gear and sliding gear along with the shift fork, and the front output shaft bearing snapring.
  22.  
  23. Install the bearing cone on the front output shaft.
  24.  
  25. Install the front output shaft bearing retainer with the shift bars and gasket.
  26.  
  27. Install the socket-headed setscrew from the front wheel drive shift fork.
  28.  
  29. Install the front output shaft rear cover and shims. Check the endplay with a dial indicator. End-play should be 0.003-0.005 in. (0.08-0.13mm). Add or remove shims to adjust. End-play is critical.
  30.  
  31. Install the rear output shaft bearing retainer and output shaft as an assembly. Torque the bolts to 30-40 ft. lbs.
  32.  
  33. Install the underdrive shift fork and rear output shaft sliding gear.
  34.  
  35. Install the socket-headed screw from the underdrive shift fork.
  36.  
  37. Install the retaining springs, shift levers and setscrews. Install the pin in each lever.
  38.  
  39. Install the end yokes. Torque the retaining lock nuts to 200-300 ft. lbs.
  40.  
  41. Install the bearings and spacers in the bore of the idler gear.
  42.  
  43. Install the idler gear and bearings with the spacers.
  44.  
  45. Install the washers.
  46.  
  47. Install the idler gear shaft.
  48.  
  49. Install the idler gear shaft lockplate bolt and lockplate. Torque the bolt to 15-20 ft. lbs.
  50.  
  51. Install the shift bar lock plungers.
  52.  
  53. Install the front drive shift bar poppet spring access hole plugs.
  54.  
  55. Install the bottom cover from the case. Torque the bolts to 15-20 ft. lbs.
  56.  

 
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