Abstract: An auxiliary box for a heavy vehicle transmission includes a shift cylinder wherein fluid drives a piston in a first direction, and a spring drives a shift fork in an opposed second direction. If fluid is supplied to drive the piston in the first direction, a first gear is engaged in the auxiliary box, and if fluid is relieved the spring drives a shift fork to engage a second piston. The invention thus eliminates some of the fluid controls and components in the prior art.

Abstract: A heavy vehicle transmission includes a multi-speed main gear box and an auxiliary gear box, such as a range or splitter gear box, coupled to the main gear box. The transmission assembly includes a shaft having an outwardly extending abutment element and a step portion. A piston constructed of non-metallic materials is mounted on the shaft. After the piston is mounted on the shaft, a retaining device is secured on the shaft for firmly retaining the piston on the shaft against the abutment element so the piston does not lean or tilt relative to the shaft to become misaligned or improperly seated, and the transmission assembly functions optimally. To accomplish this, the retaining device includes a spacing element and a locking member. The locking member is fastened on the shaft until the spacing element automatically abuts the step portion thereby retaining the piston of the assembly against the abutment element of the shaft.

Abstract: A heavy vehicle transmission auxiliary gear box has a piston housing defining internal fluid chambers. A piston shaft is further included to achieve the gear shifts in the auxiliary gear box. A yoke element is coupled to the shaft for engaging the multi-speed transmission. A piston is disposed on the shaft in the internal fluid chambers to move the shaft and the yoke element between first and second positions. Shoulder elements on the shaft prevent direct contact between the piston and the piston housing when the shaft and the yoke element are actuated between the first and second positions.

Abstract: A vehicle transmission assembly includes a main gear box that supports an auxiliary gear box assembly, such as a range gear box. The main gear box has a shaft that is coupled to a shaft of the range gear box assembly. The range gear box assembly includes selectively engageable range gears, a shifting assembly, and a range piston assembly. The range piston assembly includes a single piece housing, an air filter regulator, and a range position sensor. The sensor monitors range selection of the range gears and produces a range position signal that is sent to an electronic control unit. The air regulator is threadably attached to the single piece housing and provides air to a pneumatic piston that resides in the housing. The pneumatic piston is used to control the positioning of the range gears.