NP205 Rebuild Guide

The NP205 gear driven transfer case is considered by many to be the king of bulletproof. It was supplied in many GM, Ford, International and Dodge full-size trucks. Here is a documented tear down and rebuild of this unit. This can be done without a press, and with basic tools. Follow along and look at the photos provided then you will be ready to do this rebuild on your NP-205.

NP205 Rebuid Kits can be found at the following web sites: http://www.northwestfab.com/rebuild.html , http://offroaddesign.com/catalog/transfercaseparts.htm , http://www.jbconversions.com/index2.php?pc=3 , http://broncograveyard.com/bronco/i-21636-205-bearing-and-seal-kit.html

1. Drain the transfer case. Disconnect the rear axle drive shaft and front drive shaft from the flange at the transfer case.

2. Disconnect the shift selector rod and the speedometer cable.

3. Secure the transfer case to a transmission jack or other suitable jack, and remove the mounting bolts
Note: This is one heavy and awkward unit so use caution when lowering.

4. Lower the tranfer case and place it on the floor or work bench.

5. Clean the case so that no dirt can get inside when you start to tear it down.

6. Remove the lock nut from the front output shaft assembly.
Note: If you do not have a flange holding tool, the easiest way to remove this nut is with an impact wrench.

7. Slide yoke off of the shaft and remove the 4 bolts from the front seal/bearing retainer.

8. Remove retainer from case.
Note: The use of a pic or small screwdriver may be necessary to pry the retainer off.

9. Remove the 8 bolts from the rear bearing retainer. (Large aluminum plate)

10. Remove retainer plate from case.

11. Using a rubber mallet, tap the front output shaft assembly from the case.

12. Remove the snap ring from the front output shaft bearing and remove bearing from case.

13.Remove the 4 bolts from the input shaft seal retainer, and remove retainer from case.

14. Remove the 8 bolts from the rear drive output shaft assembly.

15. Remove assembly from case.

16. There are 15 roller bearings in the assembly, put them in a small ziplock bag.

17. Remove the snap ring from the input shaft bearing.

18. From inside the case, grab the input shaft assembly and pull the assembly out.
Note: Tapping on the input shaft with a small hammer will ease removal.

19. Using a blunt punch, drive the two 1/4 inch shift rail pin access hole plugs into the case.

20. Remove the two shift rail poppet nuts and springs from the case.

21. There is a ball bearing in each hole that can be removed using a slim magnet.
Note: If no magnet is available, you can tilt the case over and the ball bearings will fall out.

22. Position both shift rails in neutral to line up the shift fork retaining pins.

23. Using a narrow punch, tap the shift fork retaining pins out.
Note: Pins will fall to the bottom of the case.

24. Remove the range shift rail (short one) first, then the 4 wheel drive rail (long one).
Note: When you remove the rails hold the shifter forks with the other hand and remove them from the case. Keep them together.

25. Slide the rail pins out.

26. Remove the idler shaft lock nut.
Note: An impact wrench can be used for this. It is a 1- 5/16 nut so make sure you have this size socket.

27. Remove the washer behind the lock nut.

28. Remove the idler shaft rear cover.

29. Use a punch and mallet to drive the idler shaft out.

30. Roll the idler shaft assembly to the right and pull it out of the large hole.

31. Remove the PTO access cover.
Note: At this point you are finished with tear down. If you are going to paint your case, this is the time to do that.

32. Pull the shift rail seals.

33. During tear down, it is a good idea to keep the parts from each assembly together in bags.

34. Assembly begins with a freshly painted case.

35. If you need new bearings in the idler shaft assembly, drive out the old races and put new ones in.
Note: It will cost substantially less to rebuild if you don't have to replace all your bearings.

36. Here is all the parts for the idler shaft assembly.

37. Start with one of the bearings on a piece of cardboard.
Note: There are 4 shims in the assembly. Two of them go on top of this bearing.

38. Place the idler gear on top of the bearing.

39. Place the spacer on the bearing and shims. Place the other 2 shims on the top of the spacer.

40. Place the other bearing into the race.

41. Slide the assembly to the end of your workbench and place your hand under the cardboard.

42. Place the assembly into the large hole keeping the cardboard underneath.

43. Slide assebly to the left until centered on the hole, then remove cardboard.

44. Place idler shaft into hole and lightly tap until it drops through.

45. Place washer and lock nut onto shaft and tighten to 90-130 ft-lbs.
Note: Check for free rotation of idler shaft.

46. Position the idler shaft cover so that flat side faces the rear bearing retainer of the front output shaft. Install a new gasket and sealer, then tighten bolts to 15-25 ft-lbs.

47. Insert rail pins into place. Push them all the way in past the opening for the shifter rails.

48. Install new shift rail seals.

49. Start the four wheel drive shift rail (long one) into the case, solid end first, with detent notches up.
Note: Do not insert all the way yet, just insert it a few inches.

50. Position shift fork onto the shift rail with the long end facing inward.

51. Push the rail through the fork and into the neutral position.

52. Position the input gear and bearing into place and place snap ring onto bearing.

53. Start the range shift rail (short one) into the case from the front with detent notches up.
Note: Do the same as above, just insert a few inches.

54. Position the sliding clutch onto the fork. Position the clutch on the input gear and align the fork with shift rail. Then push shift rail through the fork and into the neutral position.

55. Using a long punch, install the roll pins locking the shift forks to the shift rails.
Note: Make sure the holes in the rails and the forks are lined up.

56. Install front output shaft bearing into case and install snap ring.

57. Next to go in is the front output shaft assembly.
Note: This can be a little tricky to install, so I will break it down.

58. There are three pieces that have to go in the case first.

59. This is how they are positioned on the shaft once in the case.

60. First, set the case on its side and support it with two 4"x4" wood blocks.

61. Place the thrust washer on the bearing, then the front wheel high gear goes in with the large oiling grooves facing upward. Then position the sliding clutch onto the fork.

62. Line up the thrust washer, high gear and sliding clutch with the bearing bore and insert front output shaft through the high gear and bearing assembly.

63. Install a new seal in the front seal retainer.

64. Install a new gasket, apply sealer to both sides and tighten bolts to 20-40 ft-lbs.
Note: Make sure the oil drain hole on the gasket lines up with the hole on the case.

65. Install new gasket and sealer on the rear bearing retainer (large plate) and tighten bolts to 20-40 ft-lbs.

66. Slide yoke onto front output shaft and torque lock nut to 90-130 ft-lbs.

67. Now we can install new seals and gaskets in the rear output shaft assembly.

68. Remove the lock nut from the shaft and slide yoke off.
Note: There is a rubber gasket under the lock nut.

69. Remove the five bolts from the seal retainer and remove from shaft.

70. Now you can lift the housing off of the shaft.

71. When you lift the shaft, the roller bearings will fall out. Set them aside.

72. Clean up the housing and then your ready to put it back together.

73. First put the roller bearings back into the cup using petroleum jelly to hold them in place.

74. Lower the housing on to the shaft being careful not to lose any of the roller bearings.

75. Next place the speedometer gear on the shaft.

76. Tap the bearing down into place and install snap ring.

77. Install new seal in the seal retainer.

78. Apply gasket sealer to both sides of the gasket, install the retainer and torque bolts to 20-40 ft. lbs.

79. Slide yoke into place, install rubber gasket and then lock nut. Torque nut to 90-130 ft. lbs.

80. Install a new seal in the input shaft retainer.

81. Apply gasket sealer to both sides of gasket, install retainer and torque bolts to 20-40 ft. lbs.

82. Flip upside down and using a long needle nose plier and petroleum jelly, install needle bearings.
Note: There is a spacer that must be placed under the needle bearings, use a pic to hold it up while inserting bearings.

83. Set case on its side supporting one side with a 4"x4" wood block.

84. Apply gasket sealer to both sides of gasket and drop assembly into place.
Note: Try to line up the bolt holes before setting into place, you might have to use a hammer to tap it into place.

85. Tighten bolts 20-40 ft. lbs.

86. Install poppet balls, springs, and retainer bolts. Torque bolts 15-25 ft. lbs.
Note: Poppet retainer bolts are hollow and will break easily if over-torqued.

87. Apply a small amount of sealer to the hole plugs and tap into place.

88. Apply gasket sealer to the PTO cover gasket and torque bolts 12-18 ft. lbs.

89. Fill with appropriate lubricant.

90. Install oil fill plug and tighten to 25-35 ft. lbs.

And thats all there is to it!...
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