The Warner SR-4 transmission is a 4-speed, constant mesh unit, providing synchromesh engagement in all forward gears.
See Figure 1
- Separate the transmission from the transfer case, if attached.
- Drain the lubricant from the transmission by removing the lower adapter housing bolt.
- If the shift lever housing has not been removed, place the shift lever in the neutral position, remove the retaining bolts and lift the shift lever housing from the transmission.
- Remove the flanged nut holding the offset lever to the shift rail. Remove the offset lever.
- Remove the adapter housing retaining bolts and the housing from the transmission case.
- Remove the shift control housing retaining bolts and remove the cover and gasket. Mark the location of the two dowel bolts to reinstall in their original position.
- Remove the spring clip holding the reverse lever to the reverse lever pivot bolt. Remove the reverse lever pivot bolt, allowing the removal of the reverse lever and reverse lever fork as an assembly.
- Match mark the front bearing retainer to the transmission case and remove the bearing retainer and gasket.
- Remove the large and small snaprings from the front and rear ball bearings on the input and output shafts.
- With the aid of a bearing puller tool or equivalent, remove the input shaft ball bearing and remove the input shaft from the case.
- Remove the rear (output shaft) bearing from the shaft with the aid of a bearing puller tool or equivalent.
- Remove the output shaft assembly as a unit from the transmission case. Do not allow the synchronizer sleeves to separate from the hubs during the removal.
- Push the reverse idler gear shaft rearward and remove the shaft and gear from the case.
- Using a dummy countershaft, push the countershaft to the rear of the case. Remove the cluster gear assembly and dummy countershaft as a unit, from the transmission case.
- Separate the dummy countershaft and remove the 50 needle roller bearings, spacers and thrust washers from the cluster gear.
The cluster gear front thrust washer is of a plastic material, while the rear thrust washer is metal.
- Remove the dummy shaft, bearing retainer washers and needle bearings from the countershaft gear. Clean and inspect the parts.
- Coat the bore at each end of the countershaft gear with grease to retain the needle bearings.
- While holding the dummy shaft in the gear, install the needle bearings and retainer washers in each end of the gear.
- Slide first gear off the output shaft, and remove the first speed blocker ring. Take care not to lose the sliding gear from the first and second speed synchronizer assembly.
- Clean and inspect all parts.
- Place a blocker ring on the cone of first gear, and slide the gear and ring assembly onto the output shaft. Make sure that the inserts in the synchronizer engage in the blocker ring notches.
- Install the spring pin retaining first gear to the output shaft.
- Install a blocker ring on the cone of second gear, and slide the gear and ring assembly onto the output shaft. Make sure that the inserts in the synchronizer engage in the blocker ring notches.
- Install the second gear thrust washer and new snapring on the shaft.
- Install a blocker ring on the cone of third gear, and slide the gear and ring assembly onto the output shaft. Install the third and fourth speed synchronizer. Make sure that the inserts in the synchronizer engage in the blocker ring notches.
- Install a new third and fourth gear synchronizer snapring.
- Place the first gear thrust washer (oil slinger) on the shaft and on the spring pin retaining first gear.
- Assembly end play measurements are as follows: Second gear; 0.004-0.014 in. (0.10-0.36mm), measured between the second speed gear and the thrust washer. Third/fourth synchronizer hub; 0.004-0.014 in. (0.10-0.36mm), measured between the output shaft snapring and the third speed synchronizer hub.
- Remove the detent screw, spring and plunger.
- Pull the shifter shaft rod rearward, rotating it counterclockwise.
- Remove the spring pin retaining the manual selector and interlock to the shifter shaft.
- Remove the shifter shaft from the cover taking care not to damage the seal.
- Remove the manual selector and interlock plate.
- Remove the first and second speed shifter fork. Remove the third and fourth speed shifter fork.
- Clean and inspect all parts. Replace the shifter shaft seal and welch plug, if damaged.
- Assemble the two plastic inserts to each shift fork; the two projections on the inside of the inserts fit into the blind holes in the ends of the shift forks. Insert the selector arm plates into the shift forks.
- Install the third and fourth speed shifter fork into the cover.
- Install the first and second speed shifter fork into the cover. Lubricate the shifter shaft bore with grease.
- Install the manual selector arm through the interlock plate, and position the two pieces into the cover, with the wide leg of the interlock plate towards the inside of the transmission case.
- Align the shifter shaft in the cover, and insert the shaft through the shifter forks and manual selector. Coat the shifter shaft with a light coating of grease. Make sure the detent grooves face the plunger side of the cover.
- Align the pin holes in the manual selector arm and shifter shaft. Install the spring pin flush with the surface of the selector arm.
- Install the detent plunger, spring, and plug. Tighten the plug to 8-12 ft. lbs.
- Check the operation of the shift forks in each gear position.
- Scribe alignment marks on the synchronizer and blocker rings. Remove the snapring from the front of the output shaft. Slide the third and fourth speed synchronizer assembly, blocker rings and third gear off the shaft.
- Remove the next snapring and the second gear thrust washer from the shaft. Slide second gear and the blocker ring off the shaft, taking care not to lose the sliding gear from the first and second speed synchronizer assembly. The first and second speed synchronizer hub cannot be removed from the output shaft.
- Remove the first gear thrust washer (oil slinger) from the rear of the output shaft. Remove the spring pin retaining first gear onto the shaft.
- Scribe reference marks on the hub and sleeve of the synchronizer.
- Push the sleeve from the hub of each synchronizer.
- Separate the inserts and insert springs from the hubs. Do not mix the parts between the first/second speed synchronizer and the third/fourth speed synchronizer. Clean and inspect all parts.
The first/second speed synchronizer hub is not to be removed from the shaft. They have been assembled and machined as a matched unit during manufacturing to assure concentricity.
- To assemble, position the sleeve on the hub, aligning the previously marked reference points.
- Position the three inserts per hub and install the insert springs, being sure that the bent end of the springs are seated in one of the inserts. The springs on each side of the hubs must face in opposite directions and the openings be 180 degrees apart.
- Coat the countershaft thrust washers with a petroleum jelly type lubricant and position the plastic type washer at the front of the case and the metal washer at the rear of the case.
- With the 50 needle roller bearings in place in the cluster gear and the dummy countershaft in place, install the countershaft/cluster gear assembly into the case.
- Align the cluster gear bore with the case bores and install the countershaft from the rear to the front of the case, pushing the dummy countershaft from the gear and case.
- Position the reverse idler gear with the shift lever groove facing to the front and install the shaft from the rear of the case.
- Being careful not to disturb the synchronizers, install the output shaft assembly into the transmission case. Install the fourth gear blocking ring in the third speed synchronizer sleeve, engaging the inserts on the hub with the grooves of the blocking ring.
- Install the 15 roller bearings in the input shaft pocket and retain with a petroleum jelly type lubricant. Install the input shaft into the case and engage the shaft in the third/fourth synchronizer, while the stub of the output shaft is installed in the pocket of the input shaft.
- Install the input shaft front bearing. Block the first speed gear against the rear of the case, align the bearing with the bearing bore in the case and drive the bearing completely onto the input shaft and into the transmission case.
To identify the front and rear bearings, look for a notch in the front bearing race. The rear bearing has no notch.
- Install the front bearing retaining and locating snaprings.
- Install the front bearing cap oil seal and install the cap (bearing retainer) with a new gasket to the transmission case. Install the retaining bolts.
- Install the first speed thrust washer on the output shaft with the oil grooves facing the first speed gear. Install the rear bearing onto the output shaft and into the case bearing bore.
Be sure the first gear thrust washer is engaged on the first gear roll pin before installing the rear bearing.
- Install the retaining and locating snaprings on the rear bearing and output shaft.
- Position the reverse lever in the case, on the pivot bolt and install the retaining clip. Tighten the pivot bolt. Be sure the reverse lever fork is engaged in the reverse idler gear.
- Rotate the input shaft and output shaft gears and blocking rings to insure freeness of movement. Blocking ring to gear clutch tooth face should have a clearance of 0.030 in. (0.8mm).
- Place the reverse lever in the neutral position and install the cover assembly on the transmission case. Place the two dowel bolts in their original positions and install the remaining retaining bolts.
- Install a new oil seal in the adapter housing and, using a new gasket, install the adapter housing to the transmission case.
- Install 3 pints of lubricant into the transmission.
- Install the offset lever and retain with the flanged nut.
- Depending upon the installation of the transmission into a vehicle, the shift lever housing can be installed and the transmission attached to the transfer case.