Disassembly/Assembly

Fig. 1 Exploded view of transmission:

DISASSEMBLE

1. With transmission in neutral, remove gearshift housing.
2. Lock transmission in two gears and remove output flange nut, yoke and brake drum.
3. Remove speedometer drive pinion and mainshaft rear bearing retainer.
4. Remove drive pinion bearing retainer.
5. Rotate drive pinion gear to align space in pinion gear teeth with countershaft drive gear teeth and remove drive pinion gear and tapered roller bearing from transmission.
6. Remove snap ring, washer and pilot roller bearing from recess in drive pinion gear.
7. Using a brass drift placed in front center of mainshaft, drive mainshaft to rear, then when mainshaft rear bearing clears case, remove rear bearing and speedometer gear (with spacer) using a puller.
8. Move mainshaft assembly rearward and tilt front of mainshaft up.
9. Remove roller thrust bearing, synchronizer and stop rings, and mainshaft.
10. Remove reverse idler lock screw and lockplate.
11. Using a brass drift, drive idler gear rearward, then pull shaft and lift reverse idler gear from case.
12. Remove gearing retainer at rear end of countershaft.
13. Tilt cluster gear assembly and work it out of case.
14. Using a suitable driver, remove front bearings from case.

Fig. 3 Synchronizer endplay measurement:

ASSEMBLE

1. Press front roller bearing into case until cage is flush with front of case and lubricate bearings with a light coat of grease.
2. Position transmission with front of case facing down. If uncaged roller bearings are being re-used, hold rollers in place with a light coat of grease.
3. Lower countershaft assembly into case, placing thrust washer tangs in slots in case and inserting front end of shaft into bearing.
4. Place countershaft rear roller thrust bearing on countershaft and hold in place with a light coat of grease.
5. Align countershaft assembly and install retainer gasket, retainer and bearing, then install and tighten screws.
6. Place reverse idler gear and bearing assembly in case.
7. Align reverse idler shaft so lock plate groove in shaft is properly aligned to install lock plate.
8. Tap reverse idler shaft far enough into case to start reverse gear, then while holding gear in position, tap shaft through case and gear.
9. Install lock plate, washer and screw. Ensure gear turns freely on shaft.
10. Lower rear end of mainshaft into case, then while holding first speed gear on shaft, maneuver shaft through rear bearing opening. With shaft assembly moved to rear of case, ensure third and fourth speed synchronizer and preselected shims remain in position.
11. Install roller thrust bearing.
12. Place a wood block between front of case and front of mainshaft.
13. Using a suitable size sleeve against inner race of bearing, install rear bearing onto shaft and into case until snap ring is flush against case.
14. Install drive pinion shaft and bearing assembly making sure pilot rollers remain in place.
15. Install spacer, speedometer gear, gasket and bearing retainer.
16. Place drive pinion bearing retainer over pinion shaft without gasket, then while holding retainer tight against bearing, measure clearance between retainer and case using a feeler gauge. Install a gasket shim pack 0.010-0.015 inch greater than clearance measured between retainer and case to obtain the required 0.007-0.017 inch pinion shaft endplay. After retainer bolts are tightened, recheck endplay.
17. Check for 0.050-0.070 inch synchronizer endplay after all mainshaft components are in place and properly tightened, using two sets of equal size feeler gauges. If necessary, disassemble mainshaft and change shims to retain endplay within specifications.
18. Install speedometer drive pinion, yoke flange, drum and brake assembly and output flange nut.
19. Shift gears into all speed positions and check for freedom of operation. Before installing shifter housing, fill transmission with lubricant, then oil all exposed transmission parts to avoid damage to transmission at start up.
20. Move gears into neutral position, then lower cover and new gasket over transmission, engaging forks into proper gears.
21. Install one shouldered alignment screw in each of the holes on each side of cover located next to the front hole. Check gears for freedom by shifting gears with a long screwdriver inserted in cover tower.
22. Install remaining cover screws.