GLASS 2333236 - Caterpillar

Do not increase speed while the retarder is ON.
The pressure of the air to the brake master cylinders is determined by the position of the lever for the retarder air control valve. When the lever is completely pulled down, the maximum amount of retarding is achieved.When retarder air control valve (29) is in the OFF position, the flow of air through retarder air control valve (29) is blocked. Air pressure between the control passages of brake air relay valve (12) and (43) and retarder air control valve (29) flows outward through an exhaust passage in retarder air control valve (29). The air pressure between brake air relay valve (12) and the brake master cylinders flows outward through an exhaust passage in the brake air relay valve (12). The air pressure between brake air relay valve (43) and the brake master cylinders flows outward through an exhaust passage in the brake air relay valve (43). The oil pressure that had applied the brakes returns to the brake master cylinders as the pistons are drawn up by the spring in the brake master cylinders.When the air pressure to the control passage of diverter valve (19) is blocked, the oil bypasses the torque converter