Shift Fork

Replace the shift fork in the Borg-Warner T-56 6-speed manual transmission, requiring transmission removal, disassembly of the case halves, and internal fork replacement.

Warnings

Tools required

Parts

• Shift fork (specify gear position) × 1 — Use OEM specification
• Transmission case gasket or RTV sealant × 1 — Use OEM specification
• Transmission drain plug washer × 1 — Use OEM specification
• Shift fork pad (if applicable) × 1 — Use OEM specification
• Shifter bushing kit (recommended) × 1 — Use OEM specification
• Rear main seal (recommended inspection) × 1 — Use OEM specification

Fluids

• Mopar MS-9224 or 75W-90 GL-4 manual transmission fluid — 4.2 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Disconnect negative battery cable.
3. Raise vehicle and support securely on jack stands at all four corners.
4. Remove both rear wheels to access exhaust and transmission mounting points.
5. Allow exhaust system to cool completely if vehicle was recently driven.
6. Place oil drain pan under transmission drain plug location.
7. Have transmission jack positioned and ready before beginning removal steps.

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission drain plug on the bottom of the transmission case. Using the appropriate socket, remove the drain plug and allow all fluid to drain into the catch pan. Inspect the drained fluid for metal shavings or debris that may indicate additional internal damage. Once fully drained, reinstall drain plug with new washer.
   Torque spec

   Drain Plug34 Nm (25 lb-ft)
2. 2

   Remove exhaust components
   Disconnect exhaust system from manifolds at the collector flanges. Remove 4 flange bolts per side. Support the exhaust system and remove the rear exhaust hangers to allow the complete exhaust system to be lowered and moved aside. The catalytic converters and complete exhaust may need to be removed for sufficient clearance depending on transmission jack positioning.
3. 3

   Disconnect driveshaft
   Mark the driveshaft flange alignment to the differential flange for proper reinstallation. Remove the 4 driveshaft flange bolts at the rear differential. Support the driveshaft and carefully slide it rearward to disengage the transmission output shaft. Do not allow the driveshaft to hang unsupported. Lower and remove the driveshaft from under the vehicle.
4. 4

   Disconnect shift linkage and electrical connections
   At the transmission shifter housing, disconnect the shift linkage by removing the linkage retention clips and sliding the shift rods off their ball studs. Disconnect the reverse light switch electrical connector. Disconnect the speedometer connection from the transmission (verify whether the 1992 Viper uses an electronic vehicle speed sensor connector or a mechanical speedometer cable and disconnect accordingly). Label connections if necessary for reinstallation.
5. 5

   Remove clutch slave cylinder
   Locate the hydraulic clutch slave cylinder mounted to the transmission bellhousing. Remove the 2 mounting bolts securing the slave cylinder. Carefully move the slave cylinder aside without disconnecting the hydraulic line. Support the cylinder with wire or bungee cord to prevent strain on the hydraulic line.
6. 6

   Support transmission and remove crossmember
   Position the transmission jack under the transmission and raise slightly to take the weight off the crossmember. Remove the 2 bolts securing the transmission mount to the crossmember. Remove the 4 bolts securing the crossmember to the frame rails. Lower and remove the crossmember from the vehicle.
   Torque spec

   Mounting Bolts24 Nm (18 lb-ft)
7. 7

   Remove transmission-to-bellhousing bolts
   With the transmission securely supported on the transmission jack, locate and remove all bellhousing-to-transmission bolts. There are 6 bolts securing the transmission to the bellhousing. Work around the perimeter of the bellhousing flange, ensuring all bolts are removed before attempting to separate the transmission.
8. 8

   Remove transmission from vehicle
   Carefully slide the transmission rearward on the transmission jack, keeping it level and aligned with the input shaft. The input shaft must clear the clutch disc and pilot bearing as it slides out of the bellhousing. Once clear of the input shaft, lower the transmission jack and roll the transmission out from under the vehicle. Place transmission on a sturdy workbench or transmission stand for disassembly.
9. 9

   Clean transmission exterior and remove shifter assembly
   Thoroughly clean the exterior of the transmission case to prevent contamination during disassembly. Remove the shifter assembly from the top of the transmission case by removing the mounting bolts and lifting the shifter housing assembly off. Set aside on a clean surface.
10. 10

    Remove transmission case cover bolts
    Locate all transmission case cover bolts around the perimeter of the case. Remove the transmission end cover/extension housing bolts in a criss-cross pattern. Note the location of any different length bolts for proper reassembly. Tap the cover gently with a soft mallet if necessary to break the seal. Note the location of any different length bolts for proper reassembly. Tap the case gently with a soft mallet if necessary to break the seal.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)
11. 11

    Separate transmission case halves
    Remove the transmission end cover to expose the shift rails, shift forks, and gear assemblies. Following the factory service manual, withdraw the countershaft and mainshaft assemblies as required to access the shift forks. Place removed components on a clean protected surface in the order removed.
12. 12

    Document and remove shift fork
    Take detailed photos of the shift fork position, engagement with the synchronizer sleeve, and any related components. Note the shift rail position and any detent mechanisms. Remove the shift rail retaining pin or clip securing the shift fork to its rail. Slide the shift rail out of the case, then lift the damaged shift fork out of the synchronizer sleeve engagement. Inspect the synchronizer sleeve for wear or damage from the failed fork.
13. 13

    Inspect related components
    With the shift fork removed, carefully inspect the synchronizer sleeve contact surfaces for scoring, excessive wear, or chipping. Check the shift rail bore in the case for wear or scoring. Inspect the fork pad material if separate from the fork body. Examine the detent springs and balls for proper function. Replace any components showing excessive wear.
14. 14

    Install new shift fork
    Position the new shift fork into the synchronizer sleeve groove, ensuring proper orientation matches the documented original position. The fork engagement must be centered on the sleeve. Insert the shift rail through the case bore and through the shift fork bore, aligning any detent notches. Install the shift rail retaining pin or clip to secure the fork to the rail. Verify the fork moves smoothly through its full range of motion without binding.
15. 15

    Reassemble transmission case
    Clean all old gasket material or RTV from the case and end cover mating surfaces using a plastic scraper. Ensure surfaces are completely clean and dry. Reinstall the gear/shaft assemblies and shift rails into the main case. Apply a thin continuous bead of RTV silicone gasket maker to the end cover mating surface, or install the cover gasket if equipped. Install the end cover, then install all cover bolts hand-tight first and torque in a criss-cross pattern. all case bolts hand-tight first, then torque in a criss-cross pattern.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)
16. 16

    Reinstall shifter assembly and verify operation
    Reinstall the shifter assembly onto the top of the transmission case with mounting bolts. Before fully securing, manually operate the shift mechanism through all gears to verify proper fork engagement and smooth shifting. All gears should engage positively without grinding or resistance. Once verified, torque shifter assembly bolts to specification.
17. 17

    Reinstall transmission into vehicle
    Position the transmission on the transmission jack and roll it into position under the vehicle. Raise the transmission to align the input shaft with the clutch disc spline and pilot bearing. The transmission must be level and properly aligned. Carefully slide the transmission forward onto the input shaft, ensuring the input shaft engages the clutch disc spline properly. Do not force the transmission. If it does not slide smoothly, the clutch disc may need realignment. Once the bellhousing flange is flush with the engine block, install all bellhousing-to-transmission bolts and torque in a star pattern.
18. 18

    Reinstall transmission mount and crossmember
    Raise the transmission slightly with the transmission jack. Position the crossmember into place and install the 4 crossmember-to-frame bolts. Install the 2 transmission mount-to-crossmember bolts. Torque all mounting hardware to specification. Remove the transmission jack once the transmission is fully secured.
    Torque spec

    Mounting Bolts24 Nm (18 lb-ft)
19. 19

    Reconnect clutch slave cylinder and linkage
    Reinstall the clutch slave cylinder to the bellhousing with its 2 mounting bolts. Reconnect all shift linkage to the transmission shifter housing ball studs and install retention clips. Reconnect the reverse light switch electrical connector and vehicle speed sensor connector to the transmission case.
20. 20

    Reinstall driveshaft and exhaust
    Raise the driveshaft into position and slide the front yoke onto the transmission output shaft. Align the driveshaft flange with the differential flange using the alignment marks made during removal. Install the 4 driveshaft flange bolts and torque to specification. Raise the exhaust system into position and install all exhaust hangers. Connect the exhaust collector flanges to the manifolds with new gaskets if needed. Install all exhaust flange bolts.
21. 21

    Refill transmission with fluid
    Locate the transmission fill plug on the side of the transmission case. Remove the fill plug. Using a fluid pump or squeeze bottle, add the factory-specified transmission fluid through the fill hole (verify whether the 1992 Viper T-56 requires ATF or a specific manual transmission fluid per the service manual) until fluid begins to seep from the fill hole. Install the fill plug with a new washer and torque to specification. Fill until fluid reaches the bottom of the fill hole; verify total capacity against the factory service manual specification for the 1992 Viper T-56.
    Torque spec

    Fill Plug34 Nm (25 lb-ft)

Reassembly

1. Reinstall both rear wheels and torque lug nuts to specification.
2. Lower vehicle to ground.
3. Reconnect negative battery cable.
4. Start engine and depress clutch pedal multiple times to verify hydraulic clutch operation.
5. Test drive vehicle through all gears under light load conditions before returning to service.

Verification

• With engine running and clutch depressed, shift through all gears to verify smooth engagement without grinding or resistance.
• Verify no transmission fluid leaks from the case seam, drain plug, or fill plug after test drive.
• Confirm proper synchronizer operation in all gears during test drive.
• Verify no abnormal noises from transmission during operation.
• Check that reverse lights illuminate when reverse gear is selected.
• Confirm clutch disengagement is complete and no gear clash occurs during shifts.

Related trouble codes on this vehicle

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