Planetary Gears: Service and Repair

DISASSEMBLY





1. Remove planetary snap-ring (Fig. 149).
2. Remove front annulus and planetary assembly from driving shell (Fig. 149).





3. Remove snap-ring that retains front planetary gear in annulus gear (Fig. 150).





4. Remove tabbed thrust washer and tabbed thrust plate from hub of front annulus (Fig. 151).
5. Separate front annulus and planetary gears (Fig. 151).
6. Remove front planetary gear front thrust washer from annulus gear hub.





7. Separate and remove driving shell, rear planetary and rear annulus from output shaft (Fig. 152).
8. Remove front planetary rear thrust washer from driving shell.
9. Remove tabbed thrust washers from rear planetary gear.
10. Remove lock ring that retains sun gear in driving shell. Then remove sun gear, spacer and thrust plates.

CLEANING
Clean the intermediate shaft and planetary components in solvent and dry them with compressed air. Do not spin the planetary pinion gears with compressed air.

INSPECTION
Inspect the planetary gear sets and annulus gears. The planetary pinions, shafts, washers, and retaining pins are serviceable. However, if a pinion carrier is damaged, the entire planetary gear set must be replaced as an assembly.
Replace the annulus gears if the teeth are chipped, broken, or worn, or the gear is cracked. Replace the planetary thrust plates and the tabbed thrust washers if cracked, scored or worn.
Inspect the machined surfaces of the output shaft. Be sure the oil passages are open and clear. Replace the shaft if scored, pitted, or damaged.
Inspect the sun gear and driving shell. If either component is worn or damaged, remove the sun gear rear retaining ring and separate the sun gear and thrust plate from the driving shell. Then replace the necessary component.
Replace the sun gear as an assembly if the gear teeth are chipped or worn. Also replace the gear as an assembly if the bushings are scored or worn. The sun gear bushings are not serviceable. Replace the thrust plate if worn, or severely scored. Replace the driving shell if distorted, cracked, or damaged in any way.
Replace all snap-rings during geartrain assembly. Reusing snap-rings is not recommended.

ASSEMBLY
1. Lubricate output shaft and planetary components with transmission fluid. Use petroleum jelly to lubricate and hold thrust washers and plates in position.





2. Assemble rear annulus gear and support if disassembled. Be sure support snap-ring is seated and that shoulder-side of support faces rearward (Fig. 153).
3. Install rear thrust washer on rear planetary gear. Use enough petroleum jelly to hold washer in place. Also be sure all four washer tabs are properly engaged in gear slots.
4. Install rear annulus over and onto rear planetary gear (Fig. 153).





5. Install assembled rear planetary and annulus gear on output shaft (Fig. 154). Verify that assembly is fully seated on shaft.





6. Install front thrust washer on rear planetary gear (Fig. 155). Use enough petroleum jelly to hold washer on gear. Be sure all four washer tabs are seated in slots.





7. Install spacer on sun gear (Fig. 156).





8. Install thrust plate on sun gear (Fig. 157). Note that driving shell thrust plates are interchangeable. Use either plate on sun gear and at front/rear of shell.





9. Hold sun gear in place and install thrust plate over sun gear at rear of driving shell (Fig. 158).





10. Position wood block on bench and support sun gear on block (Fig. 159). This makes it easier to align and install sun gear lock ring. Keep wood block handy as it will also be used for geartrain end play check.





11. Align rear thrust plate on driving shell and install sun gear lock ring. Be sure ring is fully seated in sun gear ring groove (Fig. 160).





12. Install assembled driving shell and sun gear on output shaft (Fig. 161).





13. Install rear thrust washer on front planetary gear (Fig. 162). Use enough petroleum jelly to hold washer in place and be sure all four washer tabs are seated.





14. Install front planetary gear on output shaft and in driving shell (Fig. 163).
15. Install front thrust washer on front planetary gear. Use enough petroleum jelly to hold washer in place and be sure all four washer tabs are seated.
16. Assemble front annulus gear and support, if necessary. Be sure support snap-ring is seated.
17. Install front annulus on front planetary (Fig. 163).





18. Position thrust plate on front annulus gear support (Fig. 164). Note that plate has two tabs on it. These tabs fit in notches of annulus hub.





19. Install thrust washer in front annulus (Fig. 165). Align flat on washer with flat on planetary hub. Also be sure washer tab is facing up.





20. Install front annulus snap-ring (Fig. 166). Use snap-ring pliers to avoid distorting ring during installation. Also be sure ring is fully seated.





21. Install planetary selective snap-ring with snap ring pliers (Fig. 167). Be sure ring is fully seated.
22. Turn planetary geartrain assembly over so driving shell is facing workbench. Then support geartrain on wood block positioned under forward end of output shaft. This allows geartrain components to move forward for accurate end play check.





23. Check planetary geartrain end play with feeler gauge (Fig. 168). Gauge goes between shoulder on output shaft and end of rear annulus support.
24. Geartrain end play should be 0.12 to 1.22 mm (0.005 to 0.048 inch). If end play is incorrect, snap-ring (or thrust washers) may have to be replaced. Snap rings are available in three different thicknesses for adjustment purposes.