Torque Converter

This procedure covers removal and replacement of the torque converter on a 2007 Ram 3500 with 5.9L Cummins diesel and automatic transmission, requiring transmission removal.

Warnings

Tools required

Parts

• Torque converter × 1 — Use OEM specification for 48RE transmission
• Transmission filter and gasket kit × 1 — Use OEM specification
• Transmission pan gasket × 1 — Use OEM specification
• Flexplate bolts × 8 — Reuse if in good condition
• Transmission to engine bolts × 1 — Reuse if in good condition
• Exhaust flange gaskets × 1 — As needed if disturbed
• Transfer case gasket/seal × 1 — Use OEM specification

Fluids

• ATF+4 — 20 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 heavy-duty jack stands at frame rails
4. Remove both rear wheels for additional clearance and stability
5. Place drain pan under transmission and drain transmission fluid from pan
6. Remove transmission pan and filter for complete drainage
7. Mark front and rear driveshaft flanges with paint or punch marks for reinstallation alignment
8. Support exhaust system with stands if removing cross-members that support exhaust

Procedure

1. 1

   Disconnect transmission cooler lines and wiring
   Disconnect transmission cooler lines at the transmission using a line wrench to prevent rounding fittings. Cap or plug all openings immediately to prevent contamination. Disconnect transmission wiring harness including speed sensors, solenoid connector, and temperature sensor. Label all electrical connections for proper reassembly.
2. 2

   Remove transfer case
   Support transfer case with a transmission jack. Remove transfer case skid plate if equipped. Disconnect transfer case shift linkage and vent hose. Remove transfer case to transmission mounting bolts. Carefully slide transfer case rearward off transmission output shaft and lower from vehicle. Note the input shaft seal condition for replacement during reassembly.
3. 3

   Remove driveshafts
   Remove rear driveshaft by removing U-bolt straps or flange bolts at differential and transfer case output. Remove front driveshaft by removing bolts at front differential and transfer case. Support driveshafts as you remove final bolts to prevent dropping. Store in a location where they will not be damaged or rolled on.
4. 4

   Disconnect shift linkage and other connections
   Disconnect transmission shift cable or linkage at transmission lever. Remove cable bracket from transmission if necessary. Disconnect any remaining vacuum lines, breather tubes, or temperature sensor wiring that was not removed earlier. On some configurations, the transmission dipstick tube must be removed from the transmission.
5. 5

   Support engine and remove crossmember
   Install engine support fixture across engine bay or use overhead hoist with load leveler to support engine weight. Position a heavy-duty transmission jack under the transmission with appropriate adapter. Remove transmission mount bolts from crossmember. Remove crossmember mounting bolts from frame and remove crossmember from vehicle. This provides clearance for transmission removal.
6. 6

   Access torque converter bolts
   Remove transmission bellhousing inspection cover to access flexplate and torque converter bolts. The 48RE transmission has the converter bolts accessible through the inspection cover. You will see the flexplate and torque converter bolt heads. Clean area around bolts to prevent contamination from entering transmission during removal.
7. 7

   Remove torque converter to flexplate bolts
   Rotate crankshaft using a socket on the crankshaft bolt to bring each torque converter bolt into view through the inspection cover opening. Remove all torque converter to flexplate bolts (verify count against the factory service manual for the 48RE - do not assume a specific quantity). Mark the flexplate and torque converter orientation before removal if possible. Keep these bolts organized as they may be reused if in good condition.
8. 8

   Remove transmission to engine bolts
   Remove all transmission to engine mounting bolts. There are typically several bolts around the bellhousing perimeter. On the Cummins diesel, note that some bolts may be different lengths - mark their locations during removal. Remove any starter bolts if starter was not previously removed. Verify all bolts are removed before attempting to separate transmission.
9. 9

   Separate and lower transmission
   With transmission jack securely positioned under transmission, carefully slide transmission rearward away from engine. The transmission must move straight back to disengage input shaft from torque converter and clear alignment dowels. Once separated approximately 2 inches, verify torque converter is staying with transmission (not stuck on flexplate). Install a C-clamp or torque converter holding strap to prevent converter from sliding out. Carefully lower transmission from vehicle, watching clearances at frame rails and exhaust components.
10. 10

    Remove torque converter from transmission
    With transmission on bench or secure stand, remove the torque converter holding clamp or strap. Carefully pull torque converter straight out of transmission. The converter will contain several quarts of fluid - have a drain pan ready. Note the depth of how far the converter was installed in the transmission (should be fully seated with at least 1/2 inch clearance from flexplate mounting surface). Inspect transmission input shaft seal and front pump bushing for wear or damage.
11. 11

    Inspect and prepare new torque converter
    Inspect flexplate for cracks, especially around bolt holes and center hub. Check flexplate runout if any vibration issues were present. Clean transmission bellhousing mating surface thoroughly. Inspect transmission front pump seal and replace if any leakage was evident. Prepare new torque converter by filling it with approximately 1 quart of fresh ATF+4 through the input shaft while rotating to distribute fluid and prime the converter.
12. 12

    Install new torque converter
    Carefully align torque converter splines with transmission input shaft and front pump drive. The converter must be installed in stages - it should 'click' into place at least twice as it engages different components. Rotate converter while applying gentle inward pressure. When fully seated, measure from front of converter hub to transmission bellhousing face - should be at least 1/2 inch recessed (verify specification in service manual). An improperly seated converter will cause immediate transmission failure. Install converter holding strap or clamp.
13. 13

    Reinstall transmission to engine
    With assistance, raise transmission into position using transmission jack. Ensure torque converter holding strap is secure. Carefully align transmission with engine, ensuring alignment dowels engage properly. Slide transmission forward onto engine, ensuring it moves smoothly without binding. If resistance is felt, do not force - lower slightly and realign. Once bellhousing is against engine block, verify torque converter has not pulled out of transmission (check that converter is still recessed from bellhousing face). Install all transmission to engine mounting bolts and tighten in a star pattern. Refer to factory service manual for specific torque values.
14. 14

    Install torque converter to flexplate bolts
    Remove torque converter holding strap. Rotate crankshaft to align torque converter bolt holes with flexplate holes. If orientation marks were made during removal, align them now. Install torque converter to flexplate bolts and tighten in a star pattern while rotating crankshaft to access each bolt. Refer to factory service manual for specific torque specifications. Verify converter rotates freely after bolts are torqued.
15. 15

    Complete reassembly and fill transmission
    Install bellhousing inspection cover. Reinstall crossmember and transmission mount. Reconnect shift linkage, wiring harnesses, cooler lines, and all other components in reverse order of removal. Reinstall transfer case, ensuring proper alignment and gasket sealing. Reinstall driveshafts in original orientation using alignment marks. Install new transmission filter and pan with new gasket. Fill transmission with ATF+4 fluid through dipstick tube - verify initial fill quantity against the factory service manual for the 48RE (typical dry fill is approximately 16-18 quarts), then add fluid as needed after running engine.

Reassembly

1. Ensure torque converter is fully seated in transmission before installation - this is critical to prevent transmission damage
2. Align all driveshaft marks made during disassembly to maintain balance
3. Use new transfer case gasket and transmission pan gasket - do not reuse old gaskets
4. Verify all electrical connections are properly seated and locked
5. Double-check that all transmission cooler line connections are tight to prevent leaks

Verification

• With vehicle still raised, start engine and verify no fluid leaks from transmission pan, cooler lines, or torque converter area
• Check transmission fluid level with engine running and transmission in park on level ground - add ATF+4 as needed to bring to proper level on dipstick
• With parking brake applied and foot on brake pedal, shift through all gear ranges verifying smooth engagement
• Test drive vehicle and verify smooth shifts in all gears with no slipping, abnormal noises, or vibrations
• After test drive, recheck fluid level when transmission is at operating temperature and top off if necessary
• Inspect under vehicle for any fluid leaks after test drive, paying special attention to pan gasket and cooler lines
• Verify no check engine light or transmission fault codes are present using a scan tool

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