Jeep CJ/Scrambler 1971-1986 Repair Guide

Dana 300 Transfer Case Overhaul

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The 300 has a cast iron case, four gear positions and employs an external floor mounted gearshift linkage for range control. It is a part time, 2 speed unit with undifferentiated high and low ranges. It is used with both manual and automatic transmission. Low range reduction is 2.6:1.

DISASSEMBLY



See Figure 1

  1. Drain the unit and remove the shift lever assembly.
  2.  
  3. Remove the bottom cover.
  4.  

The bottom cover has been coated with a sealant. Use a putty knife to break the seal and work the knife around the bottom of the cover to break it loose. Don't try to wedge the cover off.

  1. With a puller, remove the front and rear yokes.
  2.  
  3. Unbolt and remove the input shaft support from the case. The rear output shaft gear and input shaft will come with it as an assembly.
  4.  

The support has been coated with sealant. Use a putty knife to break the seal and work the knife around the bottom of the cover to break it loose. Don't try to wedge the cover off.

  1. Remove the rear output shaft clutch sleeve from the case.
  2.  
  3. Remove and discard the snap ring retaining the rear output shaft gear on the input shaft and remove the gear.
  4.  
  5. Remove and discard the input bearing snapring.
  6.  
  7. Remove the input shaft bearing from the support. Tap the end of the shaft with a soft mallet to aid removal.
  8.  
  9. Remove the input shaft bearing and end-play shims from the shaft with an arbor press.
  10.  
  11. Remove the input shaft oil seal from the support.
  12.  
  13. Unbolt and remove the intermediate shaft lockplate.
  14.  
  15. Remove the intermediate shaft. Tap the shaft out of the case using a brass punch and plastic mallet.
  16.  
  17. Remove and discard the intermediate shaft O-ring seal.
  18.  
  19. Remove the intermediate gear assembly and thrust washers.
  20.  

The thrust washers have locating tabs which must fit into notches in the case at assembly.

  1. Remove the needle bearings and spacers from the intermediate gear. There are 48 needle bearings and three spacers.
  2.  
  3. Remove the rear bearing cap attaching bolts and remove the cap. A plastic mallet will aid in removal.
  4.  

The rear bearing cap has been coated with sealant.

  1. Remove the end play shims and speedometer drive gear from the rear output shaft.
  2.  
  3. Remove and discard the rear output shaft oil seal. Remove the bearings and races from the rear cap.
  4.  
  5. Unbolt and remove the front and rear output shaft shift forks from the shift rods.
  6.  
  7. Remove the shift rods. Insert a punch through the clevis pin holes in the rods and rotate the rods while pulling them out of the case.
  8.  

The shift rods are free of the case, take care to avoid losing the shift rod poppet balls and springs.

  1. Remove the shift forks from the case.
  2.  
  3. Remove the bolts attaching the front cap to the case and remove the cap.
  4.  

The front cap has been coated with sealant.

  1. Remove the front output shaft and shift rod oil seals from the front cap.
  2.  
  3. Remove the bearing race from the front cap.
  4.  
  5. Remove the cover plate bolts and remove the plate and end play shims from the case. Keep the shims together for assembly.
  6.  
  7. Move the front output shaft toward the front of the case.
  8.  
  9. Remove the front output shaft rear bearing race.
  10.  
  11. Remove the rear output shaft front bearing. Position the case on wood blocks. Seat the clutch gear on the case interior surface and tap the shaft out of the bearing with a soft mallet.
  12.  

If the bearing is difficult to remove, an arbor press may have to be used.

  1. Remove the rear output shaft front bearing, thrust washer, clutch gear and output shaft from the case.
  2.  
  3. Remove the front output shaft rear bearing with an arbor press.
  4.  


CAUTION
Be sure to support the case with wood blocks positioned on either side of the case bore.

  1. Remove the case from the press and remove the output shaft, clutch gear and sleeve and the shaft rear bearing.
  2.  
  3. Remove the front output shaft front bearing with an arbor press and tool J-22912-01 or its equivalent.
  4.  
  5. Remove the front output shaft from the gear.
  6.  
  7. Remove the input shaft rear needle bearing from the rear output shaft using tool J-29369-1 or its equivalent. Support the shaft in a vise during removal.
  8.  
  9. Using a 3 / 8 in. drive and 7 / 16 in. socket, remove the shift rod thimbles from the case.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the Dana 300 transfer case

ASSEMBLY



Coat all parts with SAE 85W-90 oil before assembly.

  1. Apply Loctite® 220 or its equivalent to the thimbles and install them in the case.
  2.  
  3. Install the front output shaft gear on the front output shaft. Be sure that the clutch teeth on the gear face the shaft gear teeth.
  4.  
  5. Install the front bearing on the front output shaft using an arbor press. Be sure that the bearing is seated against the gear.
  6.  
  7. Install the front output shaft in the case and install the clutch sleeve and gear on the shaft.
  8.  
  9. Install the front output shaft rear bearing using an arbor press.
  10.  

Install an old yoke nut on the shaft to avoid damage to the threads.

  1. Install the input shaft needle bearings in the rear output shaft with tool J-29179 or its equivalent.
  2.  
  3. Position the rear output shaft clutch gear in the case and insert the rear output shaft into the gear.
  4.  
  5. Install the thrust washer and front bearing on the rear output shaft using an arbor press.
  6.  
  7. Install the shims and bearing on the input shaft using an arbor press.
  8.  
  9. Install a new input shaft seal.
  10.  
  11. Using a new snapring, install the input shaft and bearing in the support.
  12.  
  13. Install the rear output shaft gear on the input gear and install a new gear retaining ring.
  14.  
  15. Measure the clearance between the input gear and the gear retaining snapring using a feeler gauge. Clearance should not exceed 0.003 in. (0.08mm). If clearance is beyond tolerance, add shims between the input shaft and bearing.
  16.  
  17. Install the clutch sleeve on the rear output shaft.
  18.  
  19. Apply Loctite® 515 or equivalent to the mating surfaces of the input shaft support and install the support assembly, shaft and gear in the case. Use two support bolts to align the support on the case and tap the support into position with a soft mallet. Torque the support bolts to 10 ft. lbs.
  20.  
  21. Install the rear bearing cap front bearing race.
  22.  
  23. Install the rear bearing cap rear bearing race.
  24.  
  25. Position the rear output shaft rear bearing in the rear bearing cap.
  26.  
  27. Install the rear output shaft yoke oil seal.
  28.  
  29. Install the speedometer gear and end-play shims on the rear output shaft.
  30.  
  31. Apply Loctite® 515 or equivalent to the mating surfaces of the cap and install the rear bearing cap. Use two cap bolts to align the cap and tap it into place with a soft mallet.
  32.  
  33. Tighten the cap bolts to 35 ft. lbs.
  34.  
  35. Install the rear output shaft yoke. Torque a new locknut to 120 ft. lbs.
  36.  
  37. Clamp a dial indicator on the rear output shaft bearing cap. Position the indicator stylus so that it contacts the end of the shaft.
  38.  
  39. Pry the shaft back and forth to check end-play. End-play should be 0.001-0.005 in. (0.025-0.13mm). If play is not correct, remove or add shims between the speedometer drive gear and the output shaft rear bearing.
  40.  
  41. Install the front output shaft rear bearing race.
  42.  
  43. Install the front output shaft end play shims and cover plate. Tighten the cover plate bolts to 35 ft. lbs.
  44.  

Apply Loctite® 220 to the bolts before installation.

  1. Install the front output shaft front bearing race.
  2.  
  3. Install the front output shaft yoke oil seal.
  4.  
  5. Install the shift rod oil seals.
  6.  
  7. Install the front bearing cap, using Loctite® 515 on the mating surfaces. Use two bolts to align the cap and tap it into position with a soft mallet.
  8.  
  9. Install and tighten the bearings cap bolts to 35 ft. lbs.
  10.  
  11. Seat the rear bearing cup against the cover plate by tapping the end of the front output shaft with a plastic mallet. Mount a dial indicator on the front bearing cap and position the stylus against the end of the output shaft. Pry the shaft back and forth to check end-play. End-play should be 0.001-0.005 in. (0.025-0.13mm). If the play is not correct, add or remove shims between the cover plate and case. If shims are added seat the rear bearing cup again before checking.
  12.  
  13. Install the front output shaft yoke. Tighten the new locknut to 120 ft. lbs.
  14.  
  15. Install the front and rear output shaft shift forks.
  16.  
  17. Install the front output shaft shift rod poppet ball and spring in the front bearing cap.
  18.  
  19. Compress the poppet ball and spring and install the front output shaft shift rod part way in the case.
  20.  
  21. Insert the front output shaft shift rod through the shift fork.
  22.  
  23. Align the setscrew hole in the shift fork and rod. Install and tighten the setscrew to 14 ft. lbs.
  24.  
  25. Install the rear output shaft shift rod poppet ball and spring in the front bearing cap.
  26.  
  27. Compress the ball and spring and install the rear output shaft shift rail part way. The front output shaft shift rod should be in neutral and the interlocks seated in the front bearing cap bore.
  28.  
  29. Insert the rear output shaft shift rod through the shift fork.
  30.  
  31. Align the setscrew holes in the fork and rod. Torque the setscrew to 14 ft. lbs.
  32.  
  33. Insert tool J-25142 in the intermediate gear and install the needle bearings and spacer.
  34.  
  35. Install the intermediate gear thrust washers in the case. Make sure that the tangs are aligned with the grooves in the case. The thrust washers may be held in place with petroleum jelly.
  36.  
  37. Install a new O-ring seal on the intermediate shaft.
  38.  
  39. Position the intermediate gear in the case.
  40.  
  41. Install the intermediate shaft in the case bore. Tap the shaft into the gear until the shaft forces the tool out of the case.
  42.  
  43. Install the intermediate shaft lock plate and bolt. Torque the bolt to 23 ft. lbs.
  44.  
  45. Install the bottom cover, applying Loctite® 515 or equivalent to the mating surfaces. Install and torque the bolts to 15 ft. lbs.
  46.  
  47. Fill the case with 4 pints of SAE 85W-90W gear oil.
  48.  

 
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