Flexplate

Replace the flexplate on a 5.9L Cummins diesel engine by removing the transmission, accessing the crankshaft-to-flexplate connection, and installing a new flexplate with proper torque sequence.

Warnings

Tools required

Parts

• Flexplate (verify ring gear tooth count) × 1 — Use OEM specification
• Flexplate bolts (if reuse not recommended) × 6 — Grade 8 or OEM
• Transmission pan gasket (if pan removed) × 1 — Use OEM specification
• Transmission fluid (if draining) × 1 — Mopar ATF+4
• Transfer case output seal (recommended) × 1 — Use OEM specification

Fluids

• Mopar ATF+4 — 14 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Disconnect both battery cables, negative first
3. Raise vehicle and support securely on jack stands at frame rails
4. Remove front wheels if removing front driveshaft
5. Place drain pan under transmission and drain fluid if accessing torque converter
6. Mark driveshafts and flanges for reinstallation alignment
7. Disconnect transmission cooler lines and plug to prevent contamination
8. Disconnect transmission wiring harness and shift linkage
9. Support engine with overhead hoist or engine support fixture across fender rails

Procedure

1. 1

   Remove transfer case (4WD)
   Disconnect front and rear driveshafts first, marking orientation. Remove shift linkage and electrical connections from transfer case. Support transfer case with transmission jack. Remove transfer case mounting bolts and lower transfer case from transmission.
   Torque spec

   Sensor Mounting Bolts11 Nm (8 lb-ft)
2. 2

   Remove transmission cross member
   Support transmission with transmission jack positioned under transmission pan. Remove transmission cross member mounting bolts from frame. Lower jack slightly to provide clearance for transmission removal. Keep transmission level on jack.
   Torque spec

   Sensor Mounting Bolts11 Nm (8 lb-ft)
3. 3

   Disconnect torque converter from flexplate
   Remove transmission dust cover to access torque converter bolts. Rotate crankshaft using crankshaft pulley bolt to bring each torque converter bolt into view through access window. Remove all torque converter bolts and push torque converter back toward transmission. Mark torque converter position relative to flexplate for balance reference.
   ⚠Never rotate engine by flexplate or ring gear. Use only crankshaft pulley bolt for rotation.
   Torque spec

   Torque Converter Bolts50 Nm (37 lb-ft)
4. 4

   Remove transmission-to-engine bolts
   Remove all transmission-to-engine bell housing bolts. Note bolt lengths and positions as they vary. Some bolts may have ground straps or brackets attached. Ensure transmission jack is secure and stable.
   Torque spec

   Transmission-to-Engine Bolts55 Nm (41 lb-ft)
5. 5

   Separate and remove transmission
   Carefully slide transmission straight back away from engine to disengage input shaft from pilot bearing. Keep transmission level to prevent binding. Lower transmission on jack and remove from under vehicle. Verify torque converter remains with transmission and did not fall.
   ⚠️Transmission must move straight back to avoid damaging input shaft, pilot bearing, or flexplate. Have helper guide if needed.
6. 6

   Inspect crankshaft and pilot bearing
   With transmission removed, inspect crankshaft flange surface for cracks, wear, or damage. Check crankshaft end play by pushing/pulling crankshaft and measuring movement with dial indicator. Acceptable end play is per Cummins service manual specification (typically approximately 0.003-0.011 inches; verify exact spec). Inspect pilot bearing in crankshaft for roughness or wear. Check for oil leaks at rear main seal.
   ⚠Excessive crankshaft end play indicates thrust bearing wear and must be corrected before flexplate installation to prevent repeat failure.
7. 7

   Remove flexplate bolts
   Install flywheel holding tool to lock flexplate from rotating. Remove all flexplate-to-crankshaft bolts (verify count, typically eight on Cummins) in a crossing pattern. Note any washers or spacers. Keep bolts if reusing (inspect threads carefully for stretching or damage). Remove flexplate from crankshaft.
   Torque spec

   Flexplate Bolts85 Nm (63 lb-ft)
8. 8

   Inspect flexplate and ring gear
   Inspect removed flexplate for cracks around bolt holes, ring gear teeth for damage or wear, and overall warpage. Check for heat discoloration indicating slippage or overheating. Verify new flexplate matches tooth count and bolt pattern. Clean crankshaft flange thoroughly with brake cleaner and lint-free cloth.
   ℹ️Flexplate cracks typically start at bolt holes or flex area between crankshaft flange and ring gear. Replace if any cracks are visible.
9. 9

   Install new flexplate
   Position new flexplate on crankshaft flange with torque converter mounting surface facing transmission. Align all bolt holes. Apply light coat of thread locker to flexplate bolt threads. Install all six bolts hand tight. Verify flexplate is fully seated against crankshaft flange with no gaps.
   ⚠Flexplate is not symmetrical. Ensure correct orientation with torque converter mounting pads facing outward toward transmission.
10. 10

    Torque flexplate bolts
    Lock flexplate with holding tool. Torque flexplate bolts in a star/crossing pattern per Cummins service manual specification (commonly approximately 101 lb-ft / 137 Nm; verify exact spec and any angle requirement for your model year). Follow sequence: opposite bolts alternating around pattern. Complete at least two full passes through sequence, final pass to full torque. Recheck all bolts after completing pattern.
    ⚠Uneven torque or incorrect sequence can warp flexplate and cause premature failure. Follow crossing pattern strictly.
    Torque spec

    Flexplate Bolts85 Nm (63 lb-ft)
11. 11

    Prepare transmission for installation
    Verify torque converter is fully seated in transmission oil pump. Measure from transmission mounting surface to torque converter mounting pad. Distance should be approximately 1.5 inches or per service manual specification. Torque converter should have clicked three times during installation into pump (onto stator support, pump gear, and pump drive). Apply light grease to torque converter pilot hub.
    ⚠️Improperly seated torque converter will damage oil pump during transmission installation. Verify seating depth before proceeding.
12. 12

    Install transmission to engine
    Raise transmission on jack to align with engine. Carefully slide transmission forward, keeping input shaft aligned with pilot bearing. Rotate torque converter slightly if needed to engage splines. Transmission should slide forward smoothly without forcing. Install all transmission-to-engine bolts hand tight, then torque in crossing pattern per service manual specification (commonly approximately 50 lb-ft / 68 Nm; verify per bolt size).
    Torque spec

    Transmission-to-Engine Bolts55 Nm (41 lb-ft)
13. 13

    Connect torque converter to flexplate
    Align torque converter to flexplate, matching any balance marks if noted during removal. Rotate crankshaft to access each bolt hole through dust cover opening. Install torque converter bolts and torque per service manual specification (commonly approximately 23-35 lb-ft depending on transmission) in a star pattern. Rotate crankshaft by hand several complete revolutions to verify smooth operation with no binding or interference.
    ℹ️If torque converter has balance weights, align with flexplate balance position or heavy side of flexplate if marked.
    Torque spec

    Torque Converter Bolts50 Nm (37 lb-ft)
14. 14

    Reinstall transmission cross member and transfer case
    Raise transmission into position and install cross member mounting bolts, torquing per specification. Remove transmission jack temporarily. Reinstall transfer case to transmission with new gasket if applicable, torquing mounting bolts to specification. Reconnect driveshafts to marked positions. Reinstall dust cover bolts to 12 lb-ft.
    Torque spec

    Sensor Mounting Bolts11 Nm (8 lb-ft)
15. 15

    Reconnect components and refill fluids
    Reconnect transmission cooler lines, wiring harness, shift linkage, and all electrical connections. Reconnect transfer case linkage and wiring. Refill transmission with Mopar ATF+4 through dipstick tube (dry-fill capacity is approximately 17-19 quarts on the 47RE/48RE; add incrementally and verify with dipstick). Start engine and cycle through all gears while adding remaining fluid to proper level. Check for leaks at all connections.
    ℹ️Transmission fluid capacity varies based on torque converter and pan depth. Check level with engine running in neutral at operating temperature.

Reassembly

1. Reinstall all components in reverse order of removal
2. Torque all fasteners to specified values using crossing patterns where applicable
3. Verify all electrical connections, cooler lines, and linkages are properly secured
4. Double-check transmission fluid level after test drive and at operating temperature

Verification

• Start engine and verify no abnormal noises from transmission or flexplate area
• Check for fluid leaks around transmission pan, cooler lines, and rear main seal
• Test drive vehicle through all gears including reverse, verify smooth shifting
• Listen for flexplate noise (clicking or grinding) during acceleration and deceleration
• Recheck transmission fluid level at operating temperature with engine running in neutral
• Verify no vibration at idle or during acceleration that would indicate balance issue

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