T18 4-Speed Borg-Warner Manual Transmission Parts for Jeep CJ5

Why the T18 Transmission in the Jeep CJ5 Wears Out After Decades of Use.

The T18 transmission, alongside the T98, was one of the rugged 4-speed gearboxes in early Jeep CJ and Willys models, prized for its heavy-duty construction. Despite that durability, typical wear appears after decades of use: seals on the input and output shafts harden and start leaking, letting gear oil escape and reducing lubrication of the gear set. Bearings on the mainshaft and input shaft wear out, causing whining noises or noticeable play. The shifter boot tears or becomes brittle, letting dust and moisture into the transmission housing. Nuts loosen from vibration, and the shift mechanism's poppet ball wears down from decades of shifting. Rebuilding your T18 or replacing individual wear parts noticeably restores smoothness and sealing.

• Bearings: The rear main shaft bearing and input shaft bearing keep the gear train running smooth and quiet.
• Seal & Gasket: The T18/T98 oil seal and the input shaft oil seal cover the correct sealing option depending on model year, and the transfer case gasket seals the connection.
• Mainshaft Hardware: The mainshaft nut secures the mainshaft.
• Shift Mechanism: The shifter boot and poppet ball provide precise shifting.

Proven American Engineering for Your T18 Transmission.

All parts for the T18 transmission come from Crown Automotive, one of the leading American manufacturers of Jeep and Willys parts. Built to series-production quality, these reproductions meet OEM specifications and bring proven American engineering into your gearbox.

Your Partner for the T18 Transmission Rebuild.

Whether you're planning a full rebuild or replacing individual wear parts, we're happy to advise on installation order, torque specs, and the differences from the closely related T98 gearbox. We can also help with questions about the transfer case connection. Orders ship from our warehouse within the next business day.