VEHICLE TRANSMISSION

In general, ATF performance is defined by the service-fill specifications of passenger car and commercial vehicle transmission manufacturers. These specifications establish both testing procedures and the pass/fail criteria for the performance parameters. 

The process is used to detect the level of vehicle transmission fluid. It will cause the fahuie or delay of transmission shifting if the level is low than required value and the vehicle does not reach the drive temperature. 

Place the vehicle transmission out of gear and release all brakes. 

Applications and uses include the following thrust washers and seal rings for automotive and offroad vehicle transmissions, thermal insulators and stripper fingers for high-speed copiers, jet engine components, ball check valves, spline couplings. 

As a thermoplastic, PI can be used in a film or solid form. Most TPI versions are semicrystalline, however, amorphous versions are also available. In either case, TPI is one of the most heat-resistant thermoplastics available. It has excellent physical properties, along with chemical and wear resistance. TPI is also an inherent flame retardant. TPI applications include thrust washers and seal rings for automotive and off-road vehicle transmissions, thermal insulators and stripper fingers for high-speed copiers, jet engine components, check valve... 

With internaJ-combustion engines, automatic transmissions are frequently used these are easily justified when vehicles must make many moves during the day. Smooth as is the control afforded by automatic transmissions, it is neveriheless inferior to that provided by electric trucks, especially those with solid-state controls. Gasoline and diesel power are also used, but mostly for outdoor equipment and very-heavy-duty units. 

The many options available for lift trucks f l into two classes vehicle specialties, which include controls, transmissions, guards, etc. and accessories, which are devices that handle specific types of loads (Fig. 21-55). Included in this second category are high-lift masts, up to 7 m (24 ft) handhng attachments for circular products, such as drums and roll goods attachments such as carton clamps and the fork side-to-side shifting mechanism. 

Several different metrics are used to assess vehicle performance. Included are the time required to travel a specified distance from a standing start, the time required to accelerate from rest or from some initial speed to a specified final speed, and the speed that can be maintained on a specified upgrade without downshifting the transmission from its highest gear. In the United States, the most frequently used metric of this nature is the time required to reach 60 nipli from a standing start. 

Design features in the engine and transmission can effect seemingly subtle changes to the shape of the power available cui ve that are important to vehicle drivability. Automotive engineers normally address this issue in terms of available torque, rather than power, as a function of speed. Torque, of course, is... 

When the transmission is shifted into reverse, an idler gear (not shown in Figure 1) is interposed between appropriate gears on the countershaft and output shafts to reverse rotation of the output shaft. Wlien the vehicle is stationary with the engine running, the transmission is shifted into the neutral condition of Figure 1. 

For many years, gear shifting in the automatic transmission has been controlled hydraulically, typically in response to vehicle speed and the position of the engine inlet throttle. In recent times that control has been reassigned to an electronic computer, which facilitates gi eater smoothness and flexibility in shift control. 

Using a rear-wheel-drive vehicle as an example, a prop shaft delivers power from the transmission output, near the middle of the vehicle, to the differential that drives the wheels at the rear. If this prop shaft is designed to be stiff, which is normally the case, it could not be rigidly attached to the transmission output at one end and the differential at the other because of the differences in vertical movement between the drive wheels and the chassis. Typically, two universal joints are inserted into the drivetrain to accommodate this situation. 

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