Replace the rear main crankshaft seal on a 2014 Ram 2500 with 6.7L Cummins diesel engine, requiring transmission removal to access the seal housing at the rear of the engine block.

Warnings

Tools required

Parts

• Rear main crankshaft seal × 1 — Use OEM Mopar specification
• Rear main seal housing gasket × 1 — Use OEM Mopar specification
• Oil drain plug crush washer × 1 — Use OEM Mopar specification
• Transmission fluid filter (if servicing) × 1 — Use OEM Mopar specification
• Engine oil filter × 1 — Use OEM Mopar specification

Fluids

• Mopar 5W-20 Synthetic Blend — 13 qt
• Mopar ATF+4 — 10 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect both battery cables, negative first
3. Raise vehicle on lift or support securely on jack stands at frame contact points
4. Remove skid plates and belly pans to access transmission and oil pan
5. Drain engine oil completely and remove oil filter
6. Place transmission jack under transmission and secure with chains or straps
7. Mark driveshafts and flanges for proper reassembly alignment

Procedure

1. 1

   Disconnect transmission linkages and sensors
   Disconnect transmission wiring harness connectors on driver side of transmission. Disconnect transmission cooler lines at transmission (have drain pan ready). Disconnect shift linkage or remove shifter assembly from top of transmission. On 4WD models, disconnect transfer case wiring harness and vent hose.
2. 2

   Remove driveshafts and crossmembers
   Remove rear driveshaft by removing U-bolt caps at rear axle and sliding shaft rearward out of transmission. On 4WD models, remove front driveshaft from transfer case. Support transfer case with stand if equipped. Remove transmission crossmember mounting bolts and lower crossmember. Leave transmission supported on transmission jack.
   Torque spec

   Mounting Bolts37 Nm (27 lb-ft)
3. 3

   Disconnect exhaust and starter
   Disconnect exhaust system at manifold or downpipe connection to allow transmission clearance. Remove starter motor mounting bolts and secure starter out of way without disconnecting wiring (or disconnect and remove completely for better access). Label all electrical connections for reassembly.
4. 4

   Support engine and remove transmission
   Install engine support fixture across engine bay or attach hoist to engine lifting points. Remove all transmission-to-engine bell housing bolts (typically 6-8 bolts around perimeter). Carefully slide transmission straight back on jack, ensuring torque converter stays with transmission. Lower transmission away from vehicle. On 4WD models, transfer case may need to be separated first or removed as assembly.
   ⚠️Ensure engine is securely supported before removing final transmission bolts. Engine will shift rearward without transmission support.
   Torque spec

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

   Remove flexplate and access rear seal
   Install flywheel holding tool to prevent crankshaft rotation. Remove all flexplate-to-crankshaft bolts using star pattern. Remove flexplate and set aside on clean surface. Inspect flexplate for cracks or damage, especially around bolt holes. The rear main seal housing is now visible at rear of engine block.
   ⚠Mark flexplate orientation to crankshaft before removal to maintain engine balance during reassembly.
   Torque spec

   Flexplate Bolts85 Nm (63 lb-ft)
6. 6

   Remove rear main seal housing
   Remove all rear main seal housing bolts in cross pattern (typically 8-10 bolts). Carefully pry housing away from engine block using plastic pry tool at designated pry points. Remove housing and gasket. Clean all gasket material from engine block mating surface and housing using plastic scraper. Inspect crankshaft surface for scoring or damage where seal rides.
   ⚠Do not use metal scraper on aluminum housing or engine block surfaces. Surface damage will cause oil leaks.
   Torque spec

   Rear Main Seal Housing12 Nm (9 lb-ft)
7. 7

   Remove old seal and prepare housing
   Remove old rear main seal from housing by carefully prying out. Clean housing bore thoroughly with brake cleaner and lint-free cloth. Inspect housing for cracks or warping. Clean crankshaft seal surface with brake cleaner. Verify crankshaft has no deep grooves or scoring that would prevent proper seal contact.
8. 8

   Install new rear main seal
   Lightly lubricate new seal lip with clean engine oil. Using proper rear main seal installation tool, press new seal squarely into housing bore until fully seated and flush with housing surface. Seal lip must face toward engine (toward crankshaft). Verify seal is not cocked or damaged during installation. Apply thin bead of RTV sealant to housing gasket surface if specified by service manual, or install new dry gasket.
   ⚠Improper seal installation depth or angle will cause immediate oil leaks. Use proper installation tool to ensure seal is square and fully seated.
9. 9

   Install rear main seal housing
   Position new gasket on engine block (or apply RTV if gasket-less design). Carefully slide seal housing over crankshaft, ensuring seal lip is not damaged. Align housing bolt holes and install all bolts finger tight. Torque housing bolts in cross pattern to specification in multiple passes (50% torque, then 100% torque).
   ⚠Be extremely careful sliding housing over crankshaft to avoid cutting or rolling seal lip. Damaged seal will leak immediately.
   Torque spec

   Rear Main Seal Housing12 Nm (9 lb-ft)
10. 10

    Reinstall flexplate
    Clean flexplate bolt holes in crankshaft with brake cleaner. Position flexplate on crankshaft in original orientation (match marks aligned). Install all flexplate bolts with thread locker if specified. Install flywheel holding tool. Torque flexplate bolts to specification in star pattern in multiple passes.
    ℹ️If flexplate bolts are TTY (torque-to-yield), they must be replaced with new bolts. Check service manual specification.
    Torque spec

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

    Reinstall transmission
    Raise transmission into position on transmission jack. Verify torque converter is fully seated in transmission pump (should be recessed approximately 1/2 inch from bell housing face). Align transmission with engine and carefully slide forward, ensuring torque converter hub engages crankshaft and transmission input shaft aligns properly. Install all transmission-to-engine bolts and torque to specification in cross pattern.
    ⚠️Verify torque converter is fully seated before bolting transmission to engine. Improperly seated converter will destroy transmission pump on startup.
    Torque spec

    Transmission-to-Engine Bolts55 Nm (41 lb-ft)
12. 12

    Reconnect drivetrain components
    Install transmission crossmember and torque mounting bolts to specification. Reinstall driveshafts using alignment marks made during disassembly. Torque U-bolt caps to specification. On 4WD models, reconnect front driveshaft to transfer case. Reinstall starter motor. Reconnect exhaust system.
    Torque spec

    Mounting Bolts37 Nm (27 lb-ft)
13. 13

    Reconnect all linkages and fluids
    Reconnect transmission cooler lines and torque fittings to specification. Reconnect all transmission and transfer case wiring harnesses. Reconnect shift linkage. Install new oil drain plug crush washer and torque drain plug to specification. Install new engine oil filter. Fill engine with 13 quarts Mopar 5W-20 oil. Fill transmission with 10 quarts ATF+4 (or adjust based on actual drainage).
    Torque spec

    Oil Drain Plug35 Nm (26 lb-ft)
14. 14

    Final assembly and system checks
    Reinstall skid plates and belly pans. Reconnect battery cables (positive first, then negative). Remove engine support fixture. Double-check all bolt torques, fluid levels, and electrical connections. Verify no tools or parts remain in engine bay or under vehicle.

Reassembly

1. Transmission fluid level should be checked with engine running and transmission at operating temperature in Park position
2. Initial start may require longer cranking to build oil pressure after oil system was drained
3. If flexplate bolts were TTY type, new bolts must be used and may require additional angle torque specification

Verification

• Start engine and verify no oil leaks from rear main seal area while engine idles
• Check engine oil level after running and top off if necessary
• Test drive vehicle and verify transmission shifts properly through all gears
• After 50-100 miles, recheck engine oil and transmission fluid levels
• Inspect rear main seal area after test drive for any signs of oil seepage
• Verify no abnormal noises from transmission or engine during operation

More procedures for this vehicle