Dual Mass Flywheel

This procedure covers removal and replacement of the dual mass flywheel on a 2007 Ram 3500 with 5.9L Cummins diesel and 4WD, requiring transmission removal for access.

Warnings

Tools required

Parts

• Dual mass flywheel × 1 — Use OEM specification for 5.9L Cummins
• Flywheel bolts × 1 — One-time use stretch bolts
• Clutch disc (manual transmission) × 1 — Replace with flywheel
• Pressure plate (manual transmission) × 1 — Replace with flywheel
• Pilot bearing (manual transmission) × 1 — Use OEM specification
• Transmission input shaft seal × 1 — Inspect and replace if worn
• Rear main seal × 1 — Recommended replacement
• Transmission fluid × 1 — ATF+4 for refill

Fluids

• ATF+4 (manual transmission) — 8 qt
• 75W-90 synthetic gear oil (transfer case) — 2.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect both battery cables, negative first
3. Raise vehicle and support securely on jack stands at frame rails
4. Remove skid plates and transfer case skid plate if equipped
5. Place transmission jack under transmission for support
6. Place drain pan under transmission and transfer case drain plugs
7. Allow engine to cool completely if recently operated

Procedure

1. 1

   Drain transmission and transfer case
   Remove the drain plug from the transmission case and allow fluid to drain completely into drain pan. Remove the transfer case drain plug and drain fluid. On manual transmissions, the fill plug should be removed first to prevent vacuum lock. Collect and properly dispose of used manual transmission fluid (G56 uses a dedicated MTF such as Pennzoil Synchromesh, not ATF+4).
2. 2

   Disconnect driveshafts
   Mark the front and rear driveshaft flanges for proper reinstallation alignment. Remove the four bolts securing the rear driveshaft to the rear differential flange. Remove the four bolts securing the front driveshaft to the front differential and transfer case. Support and remove both driveshafts. Cap or plug the transfer case output to prevent debris entry.
3. 3

   Disconnect shift linkages and wiring
   For manual transmission: Disconnect the shift tower by removing the mounting bolts and lifting assembly clear. Disconnect the reverse light switch connector. Disconnect the clutch hydraulic line at the slave cylinder (if external). For 4WD, disconnect the transfer case shift motor electrical connector and vacuum lines if equipped with vacuum-actuated front axle engagement.
   ⚠Clutch hydraulic fluid may leak when disconnecting lines. Cap openings immediately to prevent air entry and fluid loss.
4. 4

   Remove crossmember and support transmission
   Position transmission jack securely under transmission pan with wood block to distribute load. Remove the transmission crossmember mounting bolts (typically four bolts). Carefully lower transmission jack slightly to provide clearance between transmission and crossmember, then remove crossmember. Ensure transmission jack is stable and secure before proceeding.
5. 5

   Disconnect transfer case from transmission
   Support the transfer case with a secondary jack or secure support. Remove the nuts/bolts securing transfer case to transmission adapter (typically 6-8 bolts around perimeter). Carefully separate transfer case from transmission by pulling rearward. Lower transfer case and remove from under vehicle. The transfer case weighs approximately 80-100 lbs.
6. 6

   Remove transmission mounting bolts
   Install engine support fixture to prevent engine from tipping when transmission is removed. Remove all transmission-to-engine bellhousing bolts (typically 6-8 bolts of varying lengths). Note the location of each bolt as lengths differ. On G56 manual transmission, remove the starter motor for clearance. Support transmission securely on transmission jack.
   ⚠️Ensure engine is properly supported before removing final transmission bolts. Engine can tip rearward causing damage or injury.
7. 7

   Remove transmission from vehicle
   With assistance, carefully slide transmission rearward on transmission jack, ensuring input shaft clears clutch disc and pilot bearing. The transmission must move straight back to avoid damaging clutch components. Once clear of dowel pins, carefully lower transmission and roll out from under vehicle. G56 transmission weighs approximately 250 lbs.
8. 8

   Remove pressure plate and clutch disc
   Install flywheel holding tool to prevent flywheel rotation. Gradually loosen pressure plate bolts in a star pattern, loosening each bolt 2-3 turns at a time to release spring tension evenly. Remove all pressure plate bolts and remove pressure plate assembly. Remove clutch disc and inspect pilot bearing in crankshaft.
9. 9

   Remove dual mass flywheel
   With flywheel holding tool still installed, remove all flywheel mounting bolts. There are typically 8 bolts securing the flywheel to the crankshaft flange. Mark flywheel position relative to crankshaft if not already indexed. Carefully remove flywheel from crankshaft, supporting its weight as it is heavy (60-80 lbs for dual mass design). Inspect crankshaft flange for damage or wear.
   ⚠Dual mass flywheel contains internal springs and dampers. Do not attempt to disassemble or drop the flywheel.
10. 10

    Inspect and prepare crankshaft flange
    Clean the crankshaft flange thoroughly with brake cleaner and lint-free cloth. Inspect flange for cracks, wear, or damage. Check crankshaft end play with dial indicator if flywheel showed unusual wear patterns. Inspect rear main seal for leakage and replace if necessary. Clean all bolt holes in crankshaft with thread chaser or tap.
11. 11

    Install new dual mass flywheel
    Ensure new flywheel matches original design and part number. Install flywheel onto crankshaft flange, aligning dowel pin or index marks. Install NEW flywheel bolts (do not reuse old stretch bolts). Using flywheel holding tool, tighten bolts in star pattern to manufacturer specifications. Without factory torque specs, consult the factory service manual for the exact flywheel bolt torque sequence and values for the 5.9L Cummins with G56 — do not rely on a generic range, as diesel flywheel bolts often require significantly higher torque with a final angle step.
    ⚠Flywheel bolts require specific torque sequence and may use torque-to-yield method. Consult factory service manual for exact specifications.
12. 12

    Install new pilot bearing and clutch components
    Install new pilot bearing into crankshaft bore using appropriate driver tool, ensuring it is fully seated. Apply small amount of high-temperature grease to pilot bearing. Position new clutch disc on flywheel with correct orientation (marked side typically faces pressure plate). Install pressure plate over clutch disc and start all bolts hand-tight. Insert clutch alignment tool through clutch disc into pilot bearing to center disc. Tighten pressure plate bolts gradually in star pattern to manufacturer specifications.
13. 13

    Reinstall transmission
    Verify clutch alignment tool is still in place. Apply thin film of high-temperature grease to transmission input shaft splines (do not over-grease). With assistance, position transmission on transmission jack and carefully align input shaft with clutch disc and pilot bearing. Slide transmission forward onto dowel pins, ensuring input shaft enters pilot bearing smoothly. If resistance is felt, do not force - recheck alignment. Once transmission is against engine block, install all bellhousing bolts and tighten to specification. Remove clutch alignment tool.
14. 14

    Reinstall transfer case and crossmember
    Clean transfer case and transmission mating surfaces. Install new gasket or apply appropriate RTV sealant if required. Position transfer case onto transmission adapter and install all mounting bolts, tightening in star pattern to specification. Reinstall transmission crossmember and mounting bolts. Raise transmission into position and install crossmember bolts. Verify all mounts are properly seated before removing transmission jack.
15. 15

    Reconnect components and refill fluids
    Reinstall starter motor if removed. Reconnect all electrical connectors including reverse light switch and transfer case shift motor. Reconnect clutch hydraulic line and bleed system if disconnected. Reconnect shift linkage and adjust if necessary. Reinstall front and rear driveshafts, aligning marks made during removal. Refill transmission with approximately 4 quarts of the specified G56 manual transmission fluid (e.g., Pennzoil Synchromesh) through fill plug until fluid reaches plug level. Refill transfer case with approximately 2 quarts ATF+4. Install drain and fill plugs to specification. Reinstall skid plates.

Reassembly

1. Reconnect battery cables, positive first, then negative
2. Lower vehicle from jack stands carefully
3. For manual transmission, bleed clutch hydraulic system if lines were disconnected
4. Check all fluid levels and top off as needed
5. Verify all fasteners are tightened to specification
6. Ensure no tools or parts remain in engine bay or under vehicle

Verification

• Start engine and verify no unusual noises from flywheel area
• For manual transmission: depress clutch pedal and verify smooth engagement and disengagement
• Test drive vehicle and verify smooth clutch operation through all gears
• Check for transmission and transfer case fluid leaks after test drive
• Verify proper 4WD engagement and driveline operation
• Listen for any vibrations or rattling that could indicate loose flywheel bolts
• After 50-100 miles, re-check transmission and transfer case fluid levels

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