4-21. EXHAUST SYSTEM.
4-21.1 Muffler and Tail Pipe.
This task covers
Tool Kit, General Mechanic,
891564 Tall Pipe
Main Engine Shutdown (see para. 2-10)
APU Shutdown (see para. 2-12)
Batteries Disconnected (see para. 4-24)
Pump Body, and Hose Body Heat Shields Removed
(see para. 4-11)
Exhaust parts can be hot enough to cause severe burns. Allow exhaust system to cool before
The muffler is heavy. To prevent personal injury, use a floor jack to support muffler during removal
Remove remote handles from foam tank drain valve and turret pipe drain valve. Pull them clear of the
underside of the truck.
Remove nuts and washers (1).
Loosen pipe clamp (2) on front of muffler. Do not remove clamp U-bolt.
While supporting the muffler, tap out the bolts (3). Twist muffler and tall pipe until it is free of exhaust
pipe. Lower to the floor.
When on the floor, remove both pipe clamps (2 and 6), and remove tall pipe (4) from muffler.
Inspect all parts for corrosion. Excessive corrosion resulting in holes or flaking is cause for rejection.
Inspect rubber shocks (7). They should not be brittle or cracked. Replace as required.
Replace any part failing inspection.