MIRROR GP 3276562 - Caterpillar

( 82V, 87V, 11W ),
130G ( 74V, 12W ) Motor GradersThe 3304 DI Engines using a Sleeve Metering Fuel System, in the above motor graders, may run backwards if the engine is stalled or lugged below the low idle rpm. If the engine runs backwards the engine oil pressure will drop to zero, exhaust will be emitted from the inlet air cleaner, and the air cleaner element will be contaminated with exhaust soot. Extended operation with the engine running backwards can result in the following: ... engine bearing damage... engine piston scuffing or seizure... vehicle moving backwards while in forward gears... shortened air filter life.
Most of the time the problem of engines running backwards can be solved by maintaining the correct engine low idle rpm specification and instructing the operators not to lug the engine below the low idle rpm. If a problem still exists after these corrective measures are taken, a new 7C1158 Air Shutoff Valve can be installed between the turbocharger outlet and the engine intake manifold. Installing this valve will assure that the engine shuts off if it attempts to run backwards. This new valve is available only as a parts service item.
Special Instruction, Form SELS0097, gives complete instructions for making the necessary modifications and installing the 7C1158 Air Shutoff Valve. No electrical or hydraulic connections are required. Installing the valve does require a modification to the cast iron pipe that connects the turbocharger and the intake manifold.