Chapter 8
Troubleshooting Transmissions, Transfer Cases, and
Differentials
Topics
1.0.0
The Standard Transmission
2.0.0
Troubleshooting Transfer Cases
3.0.0
Troubleshooting the Power Takeoff
4.0.0
Troubleshooting the Propeller Shaft
Assembly
5.0.0
Troubleshooting the Differentials
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Overview
This chapter covers the troubleshooting and overhaul of the systems and assemblies of
the drivetrain, to include the transmission, transfer case, power takeoff, propeller shaft
assembly, and differential. The information is intended as a general guide since there
are a number of different models for all the assemblies presented, but it will provide you
enough background information for troubleshooting and overhaul for each assembly.
The first topic is troubleshooting the standard or manual transmission. Although
standard transmissions are not as common as they once were, even in military vehicles,
the construction mechanic still must be accomplished in the troubleshooting and
overhaul of the standard transmission.
The next topic covers the transfer case, which is found on a great number of military
type vehicles. It can be said it is as common as the transmission since there are so
many 4x4 or 6x6 vehicles. Troubleshooting the power takeoff is another topic. The
power takeoff is what allows a dump truck to dump, a fuel truck to dispense fuel, a
transit mixer to mix cement, and a wrecker to lift its load.
The topic of troubleshooting propeller shafts is an extensive one, covering driveline
geometry, inspection, lubrication, U-joint replacement and lubrication analysis, yoke
inspection, U-joint reassembly, driveshaft installation, chassis vibration diagnosis and
PTO driveshafts.
The last topic covered is troubleshooting differentials, which provides a wide range of
exposure to the components of the differential. The drivetrain is the last bastion for a
mechanic to be a mechanic, with its gears, yokes, bushings, universal joints, splines,
etc.
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