High, or engine speed, is obtained by sliding gear No. 2 which is cored and shouldered over the end of gear No. 1, making a direct connection of the drive shaft No. 8, and the engine shaft No. 9, at this point. Reverse is obtained by meshing gear No. 3 on the drive shaft with gear No. 10, which is an extra or idle gear mounted on a stub shaft on the rear of the gear case. Idle gear No. 10 is always in mesh with gear No. 7, on the counter shaft.
Functional operation engine shafts always turn to the right or clockwise, which causes the counter shaft to turn to the left or anti-clockwise. This causes the drive shaft to turn to the right when low or intermediate speed gears are engaged, driving the car forward. Reverse, is obtained by the use of an extra gear in this way. Counter shaft turning to the left turns idle gear to the right, and this gear turning to the right, turns gear on the drive shaft to the left, and causes the car to be driven in a backward direction. In the unit power plant shown in [Fig. 112], the operation and gear shifting are identical with that of the separate gear case. The crank case of the motor is either extended or another case attached to the motor which has a compartment arranged to contain the clutch and transmission gears. This arrangement results in compactness, and does away with the supports required to carry the transmission separately.
Transmission Care.—The transmission should be thoroughly cleaned and refilled with fresh grease or heavy oil once in every thousand miles that the car is driven to prevent excessive wear and much noise. To clean, remove the plug at the bottom of the case, and the cover from the top. After the old oil has drained out, replace the plug, fill the case half full of kerosene, replace the cover, and let the motor run for a few minutes with the gears in neutral. Drain the kerosene off, and wash the case and gears off with a paint brush which has been dipped into fresh kerosene. Then examine the gears for blunt burrs and the bearings for looseness. If the gears are burred or chipped, file, or grind them down to level. If the bearings are loose they will have to be replaced, as the bearings used to carry both the counter and drive shaft are seldom provided with means of adjusting. These bearings, however, will not show wear for years if properly cared for. Next, see that the gear case is free from grit and filings, replace the drain plug, and fill the gear case to within one half inch from the drive or propeller shaft with a light graphite grease or heavy oil, and replace the cover using a new gasket.
Fig. 112. Clutch and Transmission Assembly—Unit Power Plant
CHAPTER XXX
UNIVERSAL JOINTS
Oil Plugs
Slip Joint
Oil-tight Washer
Oil Plugs
Slip Joint
Oil-tight Washer