AXLE GP-DRIVE 3253644 - Caterpillar

Exhaust Restriction
The muffler and converter will become extremly hot during engine operation. A hot muffler and converter can cause serious burns. Allow adaquate cooling time before working on or near the muffler and converter.
Excessive idling can cause the catalytic converter/muffler to plug. A plugged catalytic converter/muffler will lead to an increase in exhaust back pressure. Operating the engine in extremely cold conditions may cause the catalytic converter/muffler to plug. One indication of a plugged catalytic converter/muffler is poor engine response. If the engine is operated at low idle or at low load for 24 or more consecutive hours, the engine should be run at rated conditions for five to fifteen minutes. Running the engine at rated conditions should clean out the catalytic converter/muffler. Exhaust Back Pressure
Back pressure is the difference in the pressure between the exhaust and the atmospheric air.
Table 2
Required Tools    
Part Number    Part Name    Quantity    
1U-5470
or
198-4240     Engine Pressure Group
or
Digital Pressure Indicator     1    
Illustration 3 g00293196
1U-5470 Engine Pressure Group Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Group " for the instructions that are needed to use the 1U-5470 Engine Pressure Group. Refer to Operation Manual, NEHS0818, "Using the 198-4240 Pressure Indicator Tool Gp " for the instructions that are needed to use the 198-4240 Pressure Indicator Tool Gp.
Hot engine components can cause injury from burns. Before performing maintenance on the engine, allow the engine and the components to cool.
Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts.When working on an engine that is running, avoid contact with hot parts and rotating parts.
Illustration 4 g00780838
(A) Catalytic converter/muffler (B) 152 mm (6 inches) (C) 305 mm (12 inches) (D) Turbocharger or exhaust manifold (1) Preferred test location (2) Optional test locationThe location of the back pressure tap is important in order to obtain an accurate back pressure reading. The test location should be located on a straight length of exhaust pipe. This back pressure tap should be located as close as possible to the turbocharger or the exhaust manifold. The tap should be located at least 305 mm (12 inches) downstream of a bend. The tap should have 152 mm (6 inches) before a bend. If a continuous straight length of exhaust that is 457 mm (18 inches) is not available, the tap should be located as close as possible to the neutral axis on an elbow.If the exhaust is not equipped with a back pressure tap, the following procedure may be used in order to install a pressure tap.
Mark the position for the pressure tap.
Weld or braze a 1/8 inch NPT half coupling to the exhaust pipe.
Drill a 3.18 mm (0.125 inch) hole through the wall of the exhaust inside the half coupling.
Remove any burrs from the inside of the exhaust pipe.Use the differential pressure gauge of the 1U-5470 Engine Pressure Group in order to measure