AX5 5-Speed Bearing & Synchro Rebuild Kit, 1988-Up

A full teardown kit for the Aisin-Warner AX5 5-speed manual, the 2.5L four-cylinder box used behind the Jeep Wrangler YJ and TJ, Cherokee XJ, and Comanche MJ from 1988 up. It covers the 1988-and-later version of the case: cast iron mid-plate, snap ring on the rear of the countershaft. Check those two things before you order, because the pre-1988 AX5 uses a different bearing stack and this kit will not fit it.

Inside are the input, output and countershaft bearings, the synchronizer blocker rings, needle bearings, the front and rear seals, and the gaskets, snap rings and small hardware that come out during a strip. That is the whole wear list on an AX5. When one of these transmissions starts blocking on the 2-3 shift or grinding into third when it is cold, the blocker rings are cone-worn and the bearings behind them have gone loose enough to let the shafts walk. Replacing rings alone gets you a few thousand miles; replacing rings and bearings together is what actually fixes it.

Bench order: pull the shift tower and the extension housing, drive the countershaft rear snap ring off, split the case at the mid-plate, then press the old bearings off the shafts and stack the new synchros with the ring gap checked against the gear cone before you press anything back on. A worn ring that seats flat against the gear is worn out even if it looks new. Set input and output shaft endplay per the factory spec with the mid-plate torqued down, not loose.

This is a bearing and synchro kit only. Gears, shafts, shift forks and the case are not included, so inspect the fork pads and the 3-4 slider hub during teardown and order those separately if they are worn.