Keep in mind that it is impossible to list each and every malfunction and its possible
corrective action in this training manual. Below is a seven-step process that will enable
you to quickly isolate some problems.
2.5.2.1 Determine the Exact Nature of the Complaint
The first step when troubleshooting a transmission problem is to verify the problem.
Begin by asking the operator to describe what the vehicle is doing. Remember that the
operator may not be a mechanic so they might misinterpret the symptoms.
Now it is time to check the fluid level and road test the equipment. Once you have
determined what the problem is, proceed to the next step.
2.5.2.2 Check for Obvious Causes
Check the simple things first. You have already checked for appropriate fluid levels.
Also check to see if the transmission is overheating, or if the fluid is burnt.
If there is a shifting problem, check to see if the linkage is bent, broken, or out of
adjustment. Check for loose electrical connectors. Check to see if the vacuum
modulator has become disconnected.
If you are checking an electronically controlled transmission, see if you can get a trouble
code from the ECM.
2.5.2.3 Determine Which Component is the Most Probable Cause
Using you knowledge of transmissions, determine if the problem is due to the
mechanical system, the hydraulic system, or the electrical system.
2.5.2.4 Perform Pinpoint Tests
This step takes the most time. You need to check each system and look at the major
parts involved. Start with the easiest tests first, then move on from there.Once you have
discovered the problem, you can go on to the next step.
2.5.2.5 Check for Related Problems
At this point, you want to review what the problem was and determine if this is a stand
alone problem or if it has evolved because of something else that is wrong.
If your testing causes you to come back to the same problem as above, you have more
than likely discovered the problem.
2.5.2.6 Correct the Defect
In this step, you will need to make the necessary repairs to the transmission.
2.5.2.7 Recheck System Operation
In this step, you will need to recheck the transmission. Give it another road test. Be sure
to fully evaluate the transmission and be sure to pay attention to what you fixed to make
sure that the problem no longer exists.
NAVEDTRA 14050A
7-18