Ford Ranger 5 Speed FM145 FM146 5th Gear Problem

Is you Ranger 5 Speed Noisy in 5th Gear?

The Mitsubishi 5 speed used in the Ford Ranger from 1985 to 1992 has had a common problem with the 5th gear bearing sleeve wearing into the 5th/reverse synchronizer hub.   This problem further has caused the failure of the 5th gear on the main-shaft, causing the 5th gear to seize to the 5th/reverse hub and then break.

The problem is inherent, because the mating surface area of the 5th gear bearing sleeve is to small.  Although pressures against the hub are amplified while the transmission is at high operating temperatures, they decrease significantly when the transmission cools to ambient temperature.  This continual pattern causes the sleeve to work loose against the tth/reverse synchronizer hub and then begin to wear into the splined area of the hub.

As this wears, the preset factory clearances for end play are diminished to the point tha the 5th gear on the mainshaft bearings to heat the hub and scuffing begins to appear.  If this situation is not corrected, it will cause the 5th gear to seize to the hub, breaking the gear teeth.

Update Kit by Midwest Transmission Solves the Problem

Give the size and load characteristics of the 5th gear, correcting this problem fig_1_fm145_updateby simply changing the gear design is next to impossible.  Now only is it simple but also its is very inexpensive to install.    The entire kit includes only two pieces, a newly designed caged bearing and bearing sleeve (see Figure 1).  Further design changes directs the radial pressure fro the gear to a mor specified area on the bearing sleeve.

5th Gear Update Kit Ease to Install

During inspection for a repair or re-build of the Mitsubishi built 5 speed, closely examine the area where the 5th gear bearing sleeve contacts the 5th/reverse synchronizer hub.  If there is any noticeable wear, replace the 5th/reverse synchronizer hub, Ford p/n E5TZ7124C for the 1985 to 1987 Ranger, ESTZ07124G for the 1988-1992 Ranger, MD716397 for Ram 50 or Mitsubishi SUV and Pickup.  Also compare old design 5th needle bearing sleeve to new design (see Figure 1) and after inspection install new design 5th bearing sleeve with flange against 5th/reverse synchronizer hub (see Figure 2)

Apply assembly lube on all mating thrust surfaces and assemble remainder of main shaft.  fig_2_fm145_updateTorque mainshaft nut to 181-195 ft lbs.  Check that the .006″ – .010″ clearance is maintained between the 5th gear on the mainshaft and the 5th gear thrust washer (See Figure 1).


This installation will end your problems of poor 5th gear end clearance on the Mitsubishi built RWD 5 speed manual transmission.  Order our part number  MW990006-R   your cost $30.00 plus S&H.