Jeep CJ/Scrambler 1971-1986 Repair Guide

T-18A 4-Speed

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The Warner T-18A transmission has four forward speeds and one reverse. The T-18A transmission is synchronized in second, third and fourth speeds only.

DISASSEMBLY



See Figures 1 and 2

  1. After draining the transmission and removing the parking brake drum (or shoe assembly), lock the transmission in two gears and remove the U-joint flange, oil seal, speedometer driven gear and bearing assembly. Lubricant capacity is 6 1 / 2 pints.
  2.  
  3. Remove the output shaft bearing retainer and the speedometer drive gear and spacer.
  4.  
  5. Remove the output shaft bearing snapring, and remove the bearing.
  6.  
  7. Remove the countershaft and idler shaft retainer and the power take-off cover.
  8.  
  9. After removing the input shaft bearing retainer, remove the snaprings from the bearing and the shaft.
  10.  
  11. Remove the input shaft bearing and oil baffle.
  12.  
  13. Drive out the countershaft (from the front). Keep the dummy shaft in contact with the countershaft to avoid dropping any rollers.
  14.  
  15. After removing the input shaft and the synchronizer blocking ring, pull the idler shaft.
  16.  
  17. Remove the reverse gear shifter arm, the output shaft assembly, the idler gear, and the cluster gear. When removing the cluster, do not lose any of the rollers.
  18.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the T-18 transmission



Click image to see an enlarged view

Fig. Fig. 2: Exploded view of the T-18A transmission

Output Shaft
  1. Remove the third- and high-speed synchronizer hub snapring from the output shaft, and slide the third- and high-speed synchronizer assembly and the third-speed gear off the shaft. Remove the synchronizer sleeve and the inserts from the hub. Before removing the two snaprings from the ends of the hub, check the end play of the second-speed gear. End-play should be 0.005-0.024 in. (0.13-0.61mm).
  2.  
  3. Remove the second-speed synchronizer snapring. Slide the second-speed synchronizer hub gear off the hub. Do not lose any of the balls, springs, or plates. Pull the hub off the shaft, and remove the second-speed synchronizer from the second-speed gear. Remove the snapring from the rear of the second-speed gear, and remove the gear, spacer, roller bearings, and thrust washer from the output shaft. Remove the remaining snapring from the shaft.
  4.  

Cluster Gear

Remove the dummy shaft, pilot bearing rollers, bearing spacers, and center spacer from the cluster gear.

Reverse Idler Gear

Rotate the reverse idler gear on the shaft, and if it turns freely and smoothly, disassembly of the unit is not necessary. If any roughness is noticed, disassemble the unit.

Gear Shift Housing
  1. Remove the housing cap and lever. Be sure all shafts are in neutral before disassembly.
  2.  
  3. Tap the shifter shafts out of the housing while holding one hand over the holes in the housing to prevent loss of the springs and balls. Remove the two shaft lock plungers from the housing.
  4.  

Cluster Gear Assembly

Slide the long bearing spacer into the cluster gear bore, and insert the dummy shaft in the spacer. Hold the cluster gear in a vertical position, and install one of the bearing spacers. Position the 22 pilot bearing rollers in the cluster gear bore. Place a spacer on the rollers, and install 22 more rollers and another spacer. Hold a large thrust washer against the end of cluster gear and turn the assembly over. Install the rollers and spacers in the other end of the gear.

Reverse Idler Gear Assembly
  1. Install a snapring in one end of the idler gear, and set the gear on end, with the snapring at the bottom.
  2.  
  3. Position a thrust washer in the gear on top of the snapring. Install the bushing on top of the washer, insert the 37 bearing rollers, and then a spacer followed by 37 more rollers. Place the remaining thrust washer on the rollers, and install the other snapring.
  4.  

Output Shaft Assembly
  1. Install the second speed gear thrust washer and snapring on the output shaft. Hold the shaft vertically, and slide on the second speed gear. Insert the bearing rollers in the second-speed gear, and slide the spacer into the gear. Install the snapring on the output shaft at the rear of the second-speed gear. Position the blocking ring on the second-speed gear. Do not invert the shaft because the bearing rollers will slide out of the gear.
  2.  
  3. Press the second-speed synchronizer hub onto the shaft, and install the snapring. Position the shaft vertically in a soft-jawed vise. Position the springs and plates in the second-speed synchronizer hub, and place the hub gear on the hub.
  4.  
  5. Install the first speed gear and snapring on the shaft and press on the reverse gear.
  6.  
  7. Hold the gear above the hub spring and ball holes, and position one ball at a time in the hub, and slide the hub gear downward to hold the ball in place. Push the plate upward, and insert a small block to hold the plate in position, thereby holding the ball in the hub. Follow these procedures for the remaining balls.
  8.  
  9. Install the third speed gear and synchronizer blocking ring on the shaft.
  10.  
  11. Install the snaprings at both ends of the third and high-speed synchronizer hub. Stagger the openings of the snaprings so that they are not aligned. Place the inserts in the synchronizer sleeve, and position the sleeve on the hub.
  12.  
  13. Slide the synchronizer assembly onto the output shaft. The slots in the blocking ring must be in line with the synchronizer inserts. Install the snapring at the front of the synchronizer assembly.
  14.  

Gear Shift Housing
  1. Place the spring on the reverse gear shifter shaft gate plunger, and install the spring and plunger in the reverse gate. Press the plunger through the gate, and fasten it with the clip. Place the spring and ball in the reverse gate poppet hole. Compress the spring and install the cotter pin.
  2.  
  3. Place the spring and ball in the reverse shifter shaft hole in the gear shift housing. Press down on the ball, and position the reverse shifter shaft so that the reverse shifter arm notch does not slide over the ball. Insert the shaft part way into the housing.
  4.  
  5. Slide the reverse gate onto the shaft, and drive the shaft into the housing until the ball snaps into the groove of the shaft. Install the lock screw lock wire to the gate.
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  7. Insert the two interlocking plungers in the pockets between the shifter shaft holes. Place the spring and ball in the low and second shifter shaft hole. Press down on the ball, and insert the shifter shaft part way into the housing.
  8.  
  9. Slide the low and second shifter shaft gate onto the shaft, and install the corresponding shifter fork on the shaft so that the offset of the fork is toward the rear of the housing. Push the shaft all the way into the housing until the ball engages the shaft groove. Install the lock screw and wire that fastens the fork to the shaft. Install the third and high shifter shaft in the same manner. Check the interlocking system. Install new expansion plugs in the shaft bores.
  10.  

CASE ASSEMBLY



  1. Coat all parts, especially the bearings, with transmission lubricant to prevent scoring during initial operation.
  2.  
  3. Position the cluster gear assembly in the case. Do not lose any rollers.
  4.  
  5. Place the idler gear assembly in the case, and install the idler shaft. Position the slot in the rear of the shaft so that it can engage the retainer. Install the reverse shifter arm.
  6.  
  7. Drive out the cluster gear dummy shaft by installing the countershaft from the rear. Position the slot in the rear of the shaft so that it can engage the retainer. Use thrust washers as required to get 0.006 to 0.020 in. (0.15-0.50mm) cluster gear end play. Install the countershaft and idler shaft retainer.
  8.  
  9. Position the input shaft pilot rollers and the oil baffle, so that the baffle will not rub the bearing race. Install the input shaft and the blocking ring in the case.
  10.  
  11. Install the output shaft assembly in the case, and use a special tool to prevent jamming the blocking ring when the input shaft bearing is installed.
  12.  
  13. Drive the input shaft bearing onto the shaft. Install the thickest select-fit snapring that will fit on the bearing. Install the input shaft snapring.
  14.  
  15. Install the output shaft bearing.
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  17. Install the input shaft bearing without a gasket, and tighten the bolts only enough to bottom the retainer on the bearing snapring. Measure the clearance between the retainer and the case, and select a gasket (or gaskets) that will seal in the oil and prevent end play between the retainer and the snapring. Torque the bolts to specification.
  18.  
  19. Position the speedometer drive gear and spacer, and install a new output shaft bearing retainer seal.
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  21. Install the output shaft bearing retainer. Torque the bolts to specification, and install safety wire.
  22.  
  23. Install the brake shoe (or drum), and torque the bolts to specification. Install the U-joint flange. Lock the transmission in two gears and torque the nut to specification.
  24.  
  25. Install the power take-off cover plates with new gaskets. Fill the transmission according to specifications.
  26.  

 
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