Chrysler Full-Size Vans 1967-1988 Repair Guide

New Process NP-2500 5-Speed Overhaul

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MAJOR COMPONENT DISASSEMBLY



See Figures 1 through 10

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Fig. Fig. 1: Remove the 4 shifter bolts



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Fig. Fig. 2: Remove the access cover bolts and the cover



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Fig. Fig. 3: Remove the detent springs and bullets with a magnet



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Fig. Fig. 4: Remove the extension housing bolts, and the housing



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Fig. Fig. 5: Remove the Reverse/Overdrive shift rail, noting the position of the blocker spring



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Fig. Fig. 6: Remove the 1st/2nd shift rail



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Fig. Fig. 7: Special tool C-4982 used for certain gear removal steps



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Fig. Fig. 8: Countershaft Overdrive (OD) gear removal



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Fig. Fig. 9: Remove the mainshaft OD gear thrust washer and the anti-spin pin



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Fig. Fig. 10: Remove the R/OD synchronizer, fork, and shift rail assembly

  1. Remove the transmission from the truck.
  2.  
  3. Remove the shifter assembly bolts.
  4.  
  5. The shifter assembly is sealed with a bead of RTV sealant so it must be pried loose before removal. Clean all RTV sealant from both mating surfaces.
  6.  
  7. Remove the access cover bolts.
  8.  
  9. The access cover is sealed with a bead of RTV sealant so it must be pried loose before removal. Clean all RTV sealant from both mating surfaces.
  10.  
  11. Remove the detent springs and bullets with a magnet. Keep track of which is which.
  12.  
  13. Remove the extension housing-to-case bolts.
  14.  
  15. The extension housing is sealed with a bead of RTV sealant so it must be pried loose before removal. When pulling off the housing, hold the Reverse/Overdrive shift rail as shown in the accompanying illustration. Clean all RTV sealant from both mating surfaces.
  16.  
  17. Remove the Reverse/Overdrive shift rail and blocker spring.
  18.  
  19. Remove the tapered pins from the shift forks.
  20.  
  21. Remove the 1st/2nd shift rail.
  22.  
  23. Remove the countershaft overdrive gear snapring.
  24.  
  25. Remove the countershaft overdrive gear using tool C-4982.
  26.  
  27. Remove the mainshaft overdrive gear snapring.
  28.  
  29. Remove the mainshaft overdrive gear thrust washer and anti-spin pin.
  30.  
  31. Remove the mainshaft overdrive gear.
  32.  
  33. Remove the Reverse/Overdrive hub snapring.
  34.  
  35. Remove the Reverse/Overdrive synchronizer, fork, and rail assembly.
  36.  
  37. Remove the 3rd/4th shift rail.
  38.  
  39. Remove the 1st/2nd and 3rd/4th shift forks.
  40.  
  41. Remove the 1st/2nd and 3rd/4th shift rails.
  42.  
  43. Remove the Reverse gear.
  44.  
  45. Remove the Reverse gear thrust washer.
  46.  
  47. Remove the center support plate bolts.
  48.  
  49. Remove the gear set/support plate assembly.
  50.  

GEAR SET DISASSEMBLY



See Figures 11 through 22

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Fig. Fig. 11: Drive pinion gear cutaway area, facing the countershaft



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Fig. Fig. 12: Removing the mainshaft from the center support plate



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Fig. Fig. 13: Reverse idler gear and center support plate



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Fig. Fig. 14: Exploded view of the synchronizers used in the NP2500 transmission



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Fig. Fig. 15: Pressing the bearing off of the mainshaft



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Fig. Fig. 16: Pressing the bearing off of the input shaft



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Fig. Fig. 17: Remove the countershaft center support bearing snapring



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Fig. Fig. 18: Countershaft gear assembly and related components



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Fig. Fig. 19: Countershaft front bearing cone removal and installation



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Fig. Fig. 20: Countershaft rear bearing cone removal and installation



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Fig. Fig. 21: Rear bearing cup removal and installation



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Fig. Fig. 22: Extension housing bushing replacement

  1. Open the mainshaft center bearing snapring with a pliers and, using a plastic mallet on the center support, tap the mainshaft assembly out of the center support.
  2.  
  3. Remove the countershaft gear from the center support.
  4.  
  5. Remove the 3rd/4th synchronizer hub snapring.
  6.  
  7. Remove the 3rd/4th synchronizer assembly.
  8.  
  9. Remove the 3rd speed gear.
  10.  
  11. Remove the split thrust washer and retaining ring from the mainshaft.
  12.  
  13. Remove the 2nd speed gear.
  14.  
  15. Remove the 1st/2nd synchronizer hub snapring.
  16.  
  17. Remove the 1st/2nd synchronizer assembly.
  18.  
  19. Remove the 1st speed gear.
  20.  
  21. The synchronizers may be disassembled by removing the energizing springs.
  22.  
  23. Remove the mainshaft center bearing snapring.
  24.  
  25. Place the mainshaft in an arbor press and press off the mainshaft center bearing.
  26.  
  27. Remove the input shaft bearing retainer bolts.
  28.  
  29. Remove the retainer and discard the gasket.
  30.  
  31. Remove the large input bearing snapring.
  32.  
  33. Remove the input shaft from the case.
  34.  

There should be 16 roller bearings in the bore of the input shaft.

  1. Remove the small input shaft bearing retaining snapring.
  2.  
  3. Using an arbor press, remove the input bearing.
  4.  
  5. Remove the reverse idler shaft snapring from the center support plate.
  6.  
  7. Remove the reverse idler gear and shaft.
  8.  
  9. Remove the countershaft center bearing snapring.
  10.  
  11. Using an arbor press, remove the countershaft center bearing.
  12.  
  13. Using tool C-4983-4 and adapter, remove the front bearing cone from the countershaft.
  14.  
  15. Using an arbor press remove the front bearing cup from the case.
  16.  
  17. Using tool C-4983-5 and adapter, remove the rear bearing cone from the countershaft.
  18.  
  19. Using tools L-4454 and L-4518, remove the countershaft rear bearing cup from the extension housing.
  20.  
  21. Remove the snapring and remove the extension housing ball bearing.
  22.  
  23. Remove the extension housing yoke seal.
  24.  
  25. Drive out the extension housing bushing.
  26.  

GEAR SET ASSEMBLY



See Figures 23 and 24

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Fig. Fig. 23: Input shaft bearing installation



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Fig. Fig. 24: Checking the countershaft gear end-play

  1. Drive in a new extension housing bushing.
  2.  
  3. Install a new extension housing yoke seal.
  4.  
  5. Install the extension housing ball bearing and snapring.
  6.  
  7. Using an arbor press and tools C-4171 and C-4973, install the countershaft rear bearing cup in the extension housing.
  8.  
  9. Using an arbor press and tool C-4966, install the rear bearing cone on the countershaft.
  10.  
  11. Using an arbor press and tool C-4171, install the front bearing cup in the case.
  12.  
  13. Using an arbor press and tool C-4967, install the front bearing cone on the countershaft.
  14.  
  15. Using an arbor press and tool C-4171, install the countershaft center bearing.
  16.  
  17. Install the countershaft center bearing snapring.
  18.  
  19. Using a dial indicator, check the countershaft gear end-play with the assembly positioned in the case. End-play should be 0.03-0.13mm. Select-fit shims are available in 0.02mm increments in sizes from 1.37mm to 2.29mm.
  20.  
  21. Assemble and install the reverse idler gear and shaft.
  22.  
  23. Install the reverse idler shaft snapring on the center support plate.
  24.  
  25. Install a new input shaft retainer oil seal.
  26.  
  27. Using an arbor press and tool C-4965, install the input bearing.
  28.  
  29. Install the small input shaft bearing retaining snapring.
  30.  
  31. Install the input shaft in the case.
  32.  
  33. Install the large input bearing snapring.
  34.  
  35. Install the retainer and new gasket. Torque the bolts to 21 ft. lbs.
  36.  
  37. Assemble the 16 roller bearings in the bore of the input shaft. Hold them in place by coating them with heavy grease.
  38.  
  39. Place the mainshaft in an arbor press and press on the mainshaft center bearing.
  40.  
  41. Install the mainshaft center bearing snapring.
  42.  
  43. Assemble the synchronizers.
  44.  
  45. Install the needle bearings and snapring with the chamfered side of the snapring facing 1st gear.
  46.  
  47. Install the 1st speed gear.
  48.  
  49. Install the 1st/2nd synchronizer assembly.
  50.  
  51. Install the 1st/2nd synchronizer hub snapring.
  52.  
  53. Install the 2nd speed gear.
  54.  
  55. Install the split thrust washer and retaining ring on the mainshaft.
  56.  
  57. Install the 3rd speed gear.
  58.  
  59. Install the 3rd/4th synchronizer assembly.
  60.  
  61. Install the 3rd/4th synchronizer hub snapring.
  62.  
  63. Install the countershaft gear from the center support.
  64.  
  65. Open the mainshaft center bearing snapring with a pliers and, using a plastic mallet on the center support, tap the mainshaft assembly onto the center support.
  66.  

MAIN COMPONENT ASSEMBLY



See Figure 25

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Fig. Fig. 25: Installing the countershaft OD gear using tool C-4982

  1. Install the gear set/support plate assembly.
  2.  
  3. Install the center support plate bolts. Torque the bolts to 40 ft. lbs.
  4.  
  5. Install the Reverse gear thrust washer.
  6.  
  7. Install the Reverse gear.
  8.  
  9. Install the 1st/2nd and 3rd/4th shift forks.
  10.  
  11. Install the 3rd/4th shift rail.
  12.  
  13. Install the Reverse/Overdrive synchronizer, fork, and rail assembly.
  14.  
  15. Install the Reverse/Overdrive hub snapring.
  16.  
  17. Install the mainshaft overdrive gear.
  18.  
  19. Install the mainshaft overdrive gear thrust washer and anti-spin pin.
  20.  
  21. Install the mainshaft overdrive gear snapring.
  22.  
  23. Install the countershaft overdrive gear using tool C-4982.
  24.  
  25. Install the countershaft overdrive gear snapring.
  26.  
  27. Install the 1st/2nd shift rail.
  28.  
  29. Install the tapered pins on the shift forks.
  30.  
  31. Install the Reverse/Overdrive shift rail and blocker spring. The long end of the blocker spring faces forward.
  32.  
  33. Install the extension housing. The housing is sealed with a bead of RTV sealant rather than a gasket. Torque the bolts to 40 ft. lbs.
  34.  
  35. Install the detent springs and bullets.
  36.  
  37. Install the access cover. The access cover is sealed with a bead of RTV sealant rather than a gasket.
  38.  
  39. Install the access cover bolts. Torque the bolts to 21 ft. lbs.
  40.  
  41. Install the shifter assembly. The shifter assembly is sealed with a bead of RTV sealant rather than a gasket.
  42.  
  43. Install the shifter assembly bolts. Torque the bolts to 21 ft. lbs.
  44.  
  45. Install the transmission.
  46.  

See Figures 26, 27, 28 and 29

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Fig. Fig. 26:



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Fig. Fig. 27: Troubleshooting the Manual Transmission



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Fig. Fig. 28: Troubleshooting the Manual Transmission(cont.)



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Fig. Fig. 29: Troubleshooting the Manual Transmission(cont.)

 
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