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Replacing a leaking rear main oil seal on a Detroit Diesel DD13, DD15, or DD16 engine during a clutch job or in-frame overhaul? Follow this step-by-step professional workshop procedure to set up the extraction plate, pull the old seal safely, clean the crankshaft journal, mount the new PTFE seal dry, and draw the driver down flush to exact factory depth using the W470589004300 master kit.

Why Hammering PTFE Seals & Prying Crankshaft Flanges Causes Catastrophic Leaks

On Detroit Diesel DD Platform engines, the rear main oil seal is positioned directly behind the heavy engine flywheel. When a rear main seal leaks, oil slings across the flywheel housing, contaminating clutch friction discs and causing slippage, chatter, and complete driveline failure. Technicians attempting to replace these seals using brass drifts, screwdrivers, or makeshift installation rings face severe repair obstacles. Prying under the old seal shell with a screwdriver gouges the precision crankshaft sealing surface and flywheel housing bore. Once the steel journal is scratched, oil wicks under new seal lips continuously. Furthermore, hammering a new PTFE rear main seal into place using a mallet twists the delicate sealing lip and dislodges internal dust boots. Unlike traditional grease-lubricated rubber seals, DD Series PTFE seals must be installed completely dry and pressed squarely with 100% axial parallelism. Utilizing the 10-pound W470589004300 Master Service Kit eliminates these service risks completely. The extraction assembly threads securely to the crankshaft nose, drawing the old seal shell straight out without touching journal lands. During reassembly, the guided press driver centers perfectly over the crankshaft pilot, drawing the fresh seal down evenly until it reaches its built-in depth stop shoulder.

The 5-Step Detroit DD Series Rear Main Seal Protocol

1. Remove Transmission & Flywheel: Remove the transmission, clutch assembly, and flywheel to gain direct access to the rear crankshaft oil seal housing.
2. Mount Extraction Bridge & Pull Worn Seal: Fasten the W470589004300 extraction plate to the rear crankshaft flange using included guide bolts. Thread extraction screws into the seal shell and advance the forcing nut to draw the old seal straight out.
3. Thoroughly Clean & Inspect Crankshaft Flange: Solvent-clean the crankshaft flange and flywheel housing seal bore. Inspect the journal for scratches or burrs and polish lightly with fine emery cloth if necessary. *Ensure the sealing journal is 100% clean and completely dry.*
4. Position Fresh PTFE Seal Dry on Guide Sleeve: Mount the fresh Detroit OEM PTFE seal onto the W470589004300 installer guide pilot. *Do NOT apply grease or oil to the PTFE seal lip! PTFE seals must be installed completely dry!*
5. Advance Forcing Nut to Seat Seal to OEM Depth: Position the driver disc over the guide pilot studs and thread on the central forcing nut. Turn clockwise until the driver bottoms firmly against the built-in depth stop shoulder. Remove the tool assembly and reinstall the flywheel to factory torque specs.

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