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1992 - 1993 (AN) Dakota/Dakota Cab & Chassis
1993 (ZJ) Grand Cherokee/Grand Wagoneer
NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH THE AISIN AX-15 MANUAL TRANSMISSION BUILT BETWEEN TRANSMISSION SERIAL NO. 10900001 AND 21199999.
Transmission will not go into gear (block out) when attempting to engage reverse gear with the clutch pedal fully depressed.
A block out means that normal effort to shift the transmission will not engage the gear selected. Occasionally, on the Aisin transmission, a 'bump" will be felt when shifting into reverse. This is normal and does not indicate a block out.
The Aisin transmission also features a 5th to reverse lock out mechanism. If the customer moves the shift handle forward after entering the 5th reverse shift plane, the lock out feature will be tripped and prevent the reverse shift. Again, this is normal and does not indicate a block out.
If the clutch is not fully depressed or an attempt is made to shift too quickly after depressing the clutch, or the vehicle is moving while a reverse shift is made, grinding may occur. This again is not an indication of a block out.
The AX-15 reverse gear system is a sliding idler type that will naturally block reverse gear engagement approximately I out of 10 times. If the transmission blocks reverse more than I out of 10 tries and it is not related to any of the above conditions, it may have an incorrectly machined reverse gear.
* The AX-15 serial code numbers are located on the bottom surface of the transmission gear case.
1. Apply the parking brake and start the vehicle in neutral. Allow the vehicle to idle for 10 minutes.
2. Apply the service brake, depress the clutch pedal fully and wait five seconds. Then shift into reverse. Note if the transmission blocks.
3. Release the brakes and move the vehicle a few feet, either in reverse or Ist gear, to randomize the mating gears. Stop the vehicle and depress the clutch. Return the shifter to the neutral position. Release the clutch and apply the brakes. Depress the clutch, wait five seconds and shift into reverse. Note if the transmission blocks.
4. Repeat step three at least 20 times, noting whether the transmission blocks when shifting into reverse. if the transmission blocks 3 or more times in the 20 attempts, proceed with the repair procedure.
1 5252082 Reverse Gear
This repair involves the replacement of the transmission reverse gear.
1. Following the procedure outlined in section 21 of the appropriate service manual, remove and disassemble the transmission to gain access to the reverse gear.
2. Replace the reverse gear.
3. Assemble and install the transmission following the procedure outlined in the service manual.
POLICY: Reimbursable within the provisions of the warranty.
Labor Operation No. 21-36-04-91 AN . . . . . . . 3.9 Hrs.
YJ . . . . . . . 5.8 Hrs.
XJ . . . . . . . 5.1 Hrs.
ZJ . . . . . . . 6.2 Hrs.
Optional 4X4 Equipped 21-00-06-60 AN . . . . . . . 2.8 Hrs.
XJ . . . . . . . 1.1 Hrs.
FAILURE CODE: 7F - Reverse Gear Defect
Thanks to Barry Drodge for supplying the TSB information
This page was edited on: May 3, 2004