https://www.truck-manuals.net/mack/ 152 OPERATION MOVING THE VEHICLE — GENERAL INFORMATION Braking Avoid sudden stops. Constant sudden stops may negatively affect braking performance and driving parts. When slowing, leave the clutch (if equipped) engaged as long as possible to use the braking effect of the engine.
CAUTION When using the braking effect of the engine, final gear selection is critical. If gear selection is too high, the vehicle will buck which could cause loss of control.
Shifting Operate in a gear low enough to allow the engine to accelerate to (or maintain) governed engine speed when applying full throttle. Allowing the engine to lug causes excessive strain on the engine, which could damage pistons, rings, cylinder walls, or bearings. However, be sure not to overspeed the engine.
DANGER Always select the proper gear ratio BEFORE descending a grade (to avoid a runaway vehicle and to stay within safe and legal speed limits). Do NOT coast down hills. Gear ratios should be selected to allow the engine to operate between peak torque and rated speed.
CAUTION Do not permit a load to drive the engine above governed speed. When descending steep grades, use lower gears and watch the tachometer. Overspeeding will cause severe drivetrain damage and eventually destroy the engine.
CAUTION
