Troy-Bilt Horse Tiller Technical Manual - Page 23

SECTION 5: PTO Power Unit Transmission PTO HORSE MODEL TECHNICAL MANUAL Page 5-7 4/90 Note: Thoroughly degrease and clean all parts before inspection. Bearings - Hold the end of the stem pinion and spin the stem pinion bearing. If the bearing wobbles, or makes a growling noise, or cannot spin at all, replace the bearing with a new one. To test the other bearing, pinch it by the hole and spin it. If it wobbles, or makes a growling noise, do not reuse it. Stem Pinion - If the gear teeth are broken or excessively worn, discard the stem pinion. Fast Speed Pinion Gear - If the gear teeth are broken or excessively worn, discard the gear. Also, make sure the key is in good condition and is secure in the gear keyway. Bronze Worm Gear - If the gear teeth are damaged or excessively worn, discard the gear. Side Plugs - Check the groove where the O-ring seats; there should be no burrs or sharp edges to cut the O-ring. Use a fine file or 400 grit emery paper to smooth any rough spots. Make sure the O-ring grooves are clean. Dirt or debris will prevent the O-rings from seating properly. Transmission Housing- Make sure the transmission housing has no burrs or sharp edges that could cut the O-ring as you install the side plugs. Use a fine file or 400 grit emery paper to smooth any rough spots. Installation Before you install the pinion shaft assembly the wheel shaft assembly must first be in place. See the wheel shaft installation instructions in this section. Use Figure 5-4 as a reference for part locations in these instructions. 1. Attach the key (12) to the outside keyway in the fast speed pinion gear (11). Make sure the key does not obstruct the snap ring groove. 2. Attach the bronze worm gear (10) to the fast speed pinion gear making sure the worm gear hub is placed towards the fast speed pinion gear. To attach, set the bronze worm gear on an open vise and seat the fast speed gear with a rubber mallet. 3. Attach the (external) snap ring (9) to the fast speed pinion gear. Make sure the rounded side of the snap ring is facing towards the fast speed gear. Though not easy to observe, the snap ring has a flat side and a rounded side. 4. Using an open vise and a rubber mallet, attach the washer (8) and bearing (7) to the left side of the stem pinion (5). If you are using a sealed bearing, make sure the seal faces out. 5. Use #30 weight oil to lubricate the two bearings (7). 6. Attach the key (6) to the stem pinion. Make sure the key is flush with the edge facing the worm gear. Then use a hammer and chisel to notch the back of the keyway in the stem pinion shaft. This will prevent the key from sliding back. See Figure 5-6. 7. Place the assembled worm gear (10) and fast speed pinion gear (11) into the housing. Position the empty keyway in the fast speed gear at 12 o'clock. 8. Support the assembly by inserting your finger through the right side of the transmission housing. Insert the stem pinion assembly in from the left side of the housing, carefully aligning the key in the stem pinion with the keyway in the fast speed gear. Using a soft mallet, drive the stem 2.5 pinion in until the bearing is flush with the housing bore. Note: Make sure the key does not become dislodged from the shaft. Finish installing the stem pinion by using the pinion bearing retaining plug (2) as a driver. As you drive in the stem pinion, carefully align the gear teeth on the slow speed cast iron wheel gear with the teeth on the stem pinion. Drive the plug in until the spirol pin hole in the plug is aligned with the spirol pin hole in the transmission housing. 9. Line up the spirol pin hole in the housing with the hole in the plug and insert a punch in the hole. This will keep the stem pinion from moving when you install the bearing in the other side. 10. Install a washer (8) and shim (4A) on the right side of the stem pinion shaft. Note: Use a .062" thick shim (4A) on the right side of the stem pinion shaft. This shim is the same Figure 5-6: Notching the back of the Stem pinion.