24. Carefully pry the oil pump housing away from the case using a small flat blade screwdriver or equivalent
through the case opening Fig. 15.

Fig. 15
Oil Pump Housing Pry Point
1 - Oil Pump Housing Pry Point

25. From the front of the transmission, remove the oil pump housing.
26. Remove the B clutch spring damper Fig. 16.

Fig. 16
B Clutch
1 - B Clutch Spring Damper

M21 FSAR-TSB-4430

-12-

27. Remove the park pawl lock rod guide plate bolts and remove the plate Fig. 17.
NOTE: The transmission must be in a vertical position before the main stack is removed, so
damage to the drums does not occur.

Fig. 17
Pawl Lock Rod
1 - Pawl Lock Rod Guide Plate Bolts
2 - Pawl Lock Rod Guide Plate

28. Remove the input/output shaft and P4 annulus drum assembly from the case Fig. 18.

Fig. 18
P4 Annulus Drum Assembly
1 - P4 Annulus Drum Assembly

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M21 FSAR-TSB-4430

29. Position the input/output shaft and P4 annulus drum assembly on a press fixture Fig. 19.

Fig. 19
Input/Output Shaft And P4 Annulus Drum Assembly
1 - Input/Output Shaft And P4 Annulus Drum Assembly
2 - B Clutch Pack
3 - Assembly, Press Fixture 8925-3
4 - Splitter, Bearing/Gear 1130

30. Remove the B clutch pack.
31. Remove the P1 annulus/B clutch hub assembly from the P4 annulus drum Fig. 20.

Fig. 20
P1 Annulus/B Clutch Hub Assembly
1 - P1 Annulus/B Clutch Hub Assembly

M21 FSAR-TSB-4430

-14-

32. Remove the thrust bearing and holding plate from the P1 planetary carrier.
NOTE: The are three pieces intended to be used in multiple locations around the drum to prevent
damage from prying Fig. 21.

Fig. 21
Rings Support
1 - Rings Support

33. Position the Rings Support on the P4 annulus drum assembly to protect the drum Fig. 22.
NOTE: Pry the snap ring from the opposite side of the snap ring openings to release.
NOTE: When the snap ring is removed the internal clutch drum may drop slightly.

Fig. 22
Snap Ring
1 - Snap Ring
2 - Snap Ring Openings

34. Using a suitable tool release the snap ring by prying in and up from the opposite side of the snap ring
openings.
35. Remove the P1 planetary carrier.

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M21 FSAR-TSB-4430

36. Remove the input shaft with P2 planetary carrier from the drum assembly Fig. 23.

Fig. 23
Input Shaft
1 - Input Shaft With P2 Planetary Carrier
2 - Thrust Bearing And Washer

37. Remove the thrust bearing and washer.
38. Remove the P2 annulus/P3 sun gear from the drum assembly Fig. 24.

Fig. 24
P4 Annulus Drum
1 - P2 Annulus/P3 Sun Gear
2 - D Clutch Drum
3 - P4 Annulus Drum

39. Remove the D clutch drum from the P4 annulus drum.
NOTE: The are three pieces intended to be used in multiple locations around the drum to prevent
damage from prying.

M21 FSAR-TSB-4430

-16-

40. Remove the P4 planetary carrier/output shaft lock ring from the P4 annulus drum by gently prying the
locking tabs open and turning the lock ring to center the locating tabs in the output shaft tab openings.
Discard the lock ring and install a new lock ring during assembly Fig. 25.
NOTE: Heavy duty park system only.

Fig. 25
P4 Planetary Carrier
1 - P4 Planetary Carrier/Output Shaft Lock Ring Locking Tabs

CAUTION!
A unique transmission fluid has been developed for this transmission. This fluid is NOT compatible
with ATF+4 or any other current FCA US LLC transmission fluid. For specifics about this unique
fluid see FLUIDS, LUBRICANTS AND GENUINE PARTS.
CAUTION!
The Transmission Control Module (TCM), or Transmission Control Module Assembly (TCMA) is
extremely sensitive to Electrostatic Discharge (ESD). Always use a ground strap and follow the
ESD guidelines in Electrostatic Discharge Sensitive Devices. Failure to follow these instructions
may result in damage to the TCM/TCMA.
NOTE: If the transmission is being reconditioned (clutch/seal replacement) or replaced,
it is necessary to perform the TCM Adaptation Procedure. Refer to the detailed
service procedures available in DealerCONNECT/Service Library under: Service Info>
08 - Electrical/8E - Electronic Control Modules/Module, Transmission Control/ Module
Programming.
41. Install a NEW P4 planetary carrier/output shaft assembly into the P4 annulus drum and install park gear if
one was removed from old assembly.

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M21 FSAR-TSB-4430

42. Install the NEW P4 planetary carrier/output shaft lock ring from the P4 annulus drum by turning the lock
ring to center the lock ring tabs in the output shaft tab openings and gently staking the locking tabs closed
Fig. 26.

Fig. 26
P4 Planetary Carrier
1 - P4 Planetary Carrier/Output Shaft Lock Ring Locking Tabs

43. Install the D clutch drum into the P4 annulus drum Fig. 27.

Fig. 27
P4 Annulus Drum
1 - P2 Annulus/P3 Sun Gear
2 - D Clutch Drum
3 - P4 Annulus Drum

M21 FSAR-TSB-4430

-18-

44. Install the P2 annulus\P3 sun gear in the drum assembly Fig. 28.

Fig. 28
Input Shaft
1 - Input Shaft With P2 Planetary Carrier
2 - Thrust Bearing And Washer

45. Install the thrust bearing and washer.
46. Install the input shaft with P2 planetary carrier into the drum assembly Fig. 29.

Fig. 29
Input Shaft
1 - Input Shaft
2 - P2 Planetary Carrier

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M21 FSAR-TSB-4430

47. Install the snap ring in the orientation shown (snap ring will only install one way) with the locating tabs Fig.
30.

Fig. 30
Snap Ring
1 - Snap Ring
2 - Snap Ring Openings

48. Install the thrust bearing and holding plate onto the P1 planetary carrier.
49. Install the selectable shim to the P1 annulus/B clutch hub.
50. Install the P1 annulus\B clutch hub assembly onto the P4 annulus drum Fig. 31.

Fig. 31
P1 Annulus/B Clutch Hub Assembly
1 - P1 Annulus/B Clutch Hub Assembly

M21 FSAR-TSB-4430

-20-

51. The clutch B, dependent on transmission Julian Date, may contain wave springs that sit around each fiber.
There will be five friction plates (discs), five wave springs, five steel plates, one cover plate, one snap ring,
and one wave plate (last plate far left in figure) Fig. 32.

Fig. 32
Plates
1 - Cover Plate
2 - Friction Plates
3 - Wave Springs
4 - Steel Plates
5 - Wave Plate

52. Install the Clutch B discs and plates Fig. 33.

Fig. 33
Input/Output Shaft And P4 Annulus Drum Assembly
1 - Input/Output Shaft And P4 Annulus Drum Assembly
2 - B Clutch Pack
3 - Assembly, Press Fixture 8925-3
4 - Splitter, Bearing/Gear 1130

53. Install the snap ring.
NOTE: The transmission must be in a vertical position when installing the main stack, so damage
to the drums does not occur.

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M21 FSAR-TSB-4430

54. Install the input/output shaft and P4 annulus drum assembly into the case Fig. 34.

Fig. 34
P4 Annulus Drum Assembly
1 - P4 Annulus Drum Assembly

55. Install the park pawl lock rod onto the fork Fig. 35.

Fig. 35
Pawl Lock Rod
1 - Pawl Lock Rod Guide Plate Bolts
2 - Pawl Lock Rod Guide Plate

56. Position the park pawl lock rod guide plate, install the three park pawl lock rod guide plate retaining bolts.

M21 FSAR-TSB-4430

-22-

57. Install the clutch B damper spring on the assembly Fig. 36.

Fig. 36
B Clutch
1 - B Clutch Spring Damper

58. Carefully position the oil pump housing assembly into the case.
59. Install the new input shaft O-ring Fig. 37.
NOTE: Firmly press the oil pump in place before drawing it in with bolts.

Fig. 37
Input Shaft O-ring
1 - Input Shaft O-ring

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M21 FSAR-TSB-4430

60. Install a NEW transmission oil pump assembly to case bolts Fig. 38.
NOTE: The manual park release lever can be reversed to release tension and ease the installation
of the valve body assembly.

Fig. 38
Oil Pump Housing
1 - Oil Pump Housing Bolts

61. Temporarily install the Manual Park Release (MPR) lever to release tension on the shift fork as follows Fig.
39:
a. Install the MPR lever 180 degrees offset from its original position.
b. Install the MPR retaining nut and hand tighten.
c. Turn the MPR lever and using a tie strap, secure the lever into position so the park release fork is in the
same position as it was before valve body assembly removal.

Fig. 39
Manual Park Release
1 - MPR Lever Retaining Nut
2 - MPR Lever
3 - Tie Strap

M21 FSAR-TSB-4430

-24-

62. Replace the fluid transfer tube O-rings and install the fluid transfer tube to the transmission case Fig. 40.

Fig. 40
Fluid Port
1 - Fluid Tube

63. Install the Pins, Valve Body Alignment in the transmission case as guides for the valve body assembly.
NOTE: Make sure the shift fork lines up properly.
64. Using the valve body alignment pins position the valve body assembly to the transmission.
NOTE: After several bolts have been hand tightened, remove the guide pins.
65. Install the valve body assembly bolts Fig. 41.

Fig. 41
Valve Body Assembly

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M21 FSAR-TSB-4430

66. Using Guide Sleeve 10377, carefully install the electrical harness guide sleeve into the transmission case
Fig. 42.

Fig. 42
Electrical Harness Insulator
1 - Remover/Installer, Guide Sleeve 10377
2 - Electrical Harness Insulator

67. Latch the electrical connector lock by pushing down Fig. 43.

Fig. 43
Valve Body Assembly
1 - Valve Body Assembly End Retainer Bolt
2 - Valve Body Assembly End Retainer Bolt
3 - Electrical Connector Lock

68. Install the valve body end bolt and electrical connector lock bolt.

M21 FSAR-TSB-4430

-26-

69. When installing the Output Speed Sensor (OSS) into the case, take care to position the OSS guide pin as
shown below or damage to the sensor may result. This is the incorrect alignment of the pin Fig. 44.

Fig. 44
Output Speed Sensor Incorrect
70. This is the correct installation and pin alignment Fig. 45.

Fig. 45
Output Speed Sensor Correct

-2771. Install the output speed sensor and the bolt in the case and tighten to Fig. 46.

Fig. 46
Output Speed Sensor
1 - Output Speed Sensor Bolt

72. If equipped, install the HIS and bolts Fig. 47.

Fig. 47
Hydraulic Impulse Oil Storage
1 - Hydraulic Impulse Oil Storage (HIS) Connector
2 - Hydraulic Impulse Oil Storage (HIS) Bolts

73. Connect the HIS electrical connector.

M21 FSAR-TSB-4430

M21 FSAR-TSB-4430

-28-

74. Remove the tie strap and return the manual release lever to the original position Fig. 48.

Fig. 48
Manual Park Release
1 - MPR Lever
2 - MPR Lever Retaining Nut

75. Install the manual release lever nut.
76. Position the transmission oil pan and gasket Fig. 49.

Fig. 49
Transmission Oil Pan
1 - Transmission Oil Pan Bolts
2 - Transmission Oil Pan

77. Install the transmission oil pan bolts.
NOTE: For 4X4 only.
CAUTION!
The seal must be installed flush with the case. Driving the seal deeper could damage the seal
causing a leak.

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M21 FSAR-TSB-4430

78. Position the new output shaft seal over the output shaft and against the transmission case Fig. 50.

Fig. 50
Transmission Output Shaft Seal
1 - Transmission Output Shaft Seal

79. Using a Seal Installer, install the output shaft seal Fig. 51.

Fig. 51
Output Shaft
1 - Seal Installer
2 - Output Shaft Seal

M21 FSAR-TSB-4430

-30-

80. For 4X4 ONLY if equipped, position the extension housing and install the extension housing bolts Fig. 52.

Fig. 52
Extension Housing
1 - Extension Housing Bolts
2 - Extension Housing

81. For 2WD vehicles, remove old seal from the output flange and replace with new output flange O-ring Fig.
53.

Fig. 53
Output Flange
1 - Output Flange
2 - O-ring

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M21 FSAR-TSB-4430

82. For 2WD vehicles, install the output shaft flange Fig. 54.

Fig. 54
Transmission Output Flange
1 - Transmission Output Flange
2 - Transmission Output Flange Nut
3 - Transmission Output Flange Nut Stake

83. For 2WD vehicles, install a new output shaft flange nut and washer using a 34 mm, 12 point socket and to
hold the flange.
84. For 2WD vehicles, stake the nut.
85. Install the torque converter Fig. 55 Refer to the detailed service procedures available in DealerCONNECT/
Service Library under: Service Info> 21 - Transmission and Transfer Case/Automatic/Torque Converter/
Installation.

Fig. 55
Torque Converter
1 - Torque Converter

86. NOTE: For WL 4x4 Only.
Install green o-ring to output shaft Fig. 56.

Fig. 56
Green O-Ring
1 - Green O-Ring

87. Before installing the transmission in the vehicle, pre-fill the transmission as outlined in Fill Transmission
After Service. Refer to the detailed service procedures available in DealerCONNECT/Service Library
under: Service Info>21 - Transmission and Transfer Case/Automatic/Standard Procedure.
88. Install the transmission. Refer to the detailed service procedures available in DealerCONNECT/Service
Library under: Service Info>21 - Transmission and Transfer Case / Automatic - 8HP50/850RE / Installation.
89. Use wiTECH to complete Quick Learn Procedure and clear any DTCs.
POLICY:
Reimbursable within the provisions of the warranty.
This bulletin is supplied as technical information only and is not an authorization for repair. No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwise, without written permission of FCA US LLC.