https://www.truck-manuals.net/mack/ 176 OPERATION MACK T310M, T310ME and T310MLR Shifting Instructions
CAUTION Make sure air pressure is at least 90 psi and unit is at operating temperature before making range shifts. Always start in LO range. This also applies to dynamometer testing. When the truck is stationary, do NOT shift into HI range and then start moving the truck. Otherwise, damage to the synchronizer may result.
The T310M is a range-shifted transmission which has 10 forward speeds. There is a LO and HI auxiliary compound section controlled by an air-shift selector on the shifter. This compound section is equipped with a synchronizer to facilitate LO-HI range shifting. The T310M transmission also provides a multi-speed reverse feature by means of reverse gearing in the compound case which works in conjunction with LO-LO, first and second speed gears in the main box. The air-shift selector must be moved to the R (REVERSE) position in order to utilize the multi-speed reverse feature. LO range provides six low ratios for six forward gears in the T310M. HI range provides four additional forward gears which can be shifted in the standard manner. Remember, however, to double-clutch when moving up or down through the gears. For normal highway use, start in LO range, first gear and shift through second, third and fourth. The LO-LO and LO positions in LO range for this transmission are designed for use in off-highway and slow-moving operations such as curb pouring, material spreading, heavy load/steep grade. REVERSE is used in LO range for four reverse speeds. Upshift — Begin in first gear (shown as 1/5 on shift pattern diagram) with air-shift selector in LO range. Upshift to second gear (2/6 on shift pattern diagram) LO range in the normal manner (double-clutching). When ready to upshift again, depress the clutch pedal and release the accelerator pedal in the normal manner. Repeat this shifting pattern through the remaining gears up to fourth speed (4/8 on shift pattern diagram). When maximum engine RPM has been reached in fourth gear, flip the air-shift selector to HI range (preselect), then double-clutch and shift to fifth gear. As the shift lever passes through NEUTRAL, it will put the transmission in HI range. Continue to upshift through normal sixth, seventh and eighth gears, while double-clutching.
