Manual drivetrain and Axles

Clutch and Manual Transmission Diag Examples

Auto Occupations

In this lesson, we will discuss a couple of manual transmissions and clutch symptoms and diagnostics.

First the General Inspection

• What are some things I can quickly inspect on a manual transmission and clutch system?

Open Ended

What are some things I can quickly inspect on a manual transmission and clutch system?

General Inspections Points

• 1. Transmission Fluid Level and Condition (We can review this if needed)

• Clutch Hydraulic Fluid (if equipped)

• Evaluate the clutch

• Inspect Gear Shift Mechanism (Binding, Bent, Broken)

• Evaluate the Transmission (Hard Shift, Grinding Gears, Excessive Noise)

The Road Test (Do not drive with low transmission fluid)

• 1. Start the engine

• 2. Evaluate the noise in NEUTRAL while parked

• Is there a noise with the clutch pressed/released?

• Noise with a change in RPM?

• Does it go through all gears smoothly?

• Noise in a specific gear/speed?

• Noise only under load, coasting, clutch in/out?

Typical Clutch Concerns

• Clutch Slippage

• Clutch chatter or shudder

• The clutch pedal feels spongy or excessive travel or does not disengage

• Clutch drag hard to shift

• Clutch pedal pulsation

• Clutch-related vibration

• Excessive noise

Let's work through an example...

• 2015 Ford Mustang 5.0L MT

• Customer States Transmission is difficult to shift when cold

• The transmission starts to shift normally when it warms up.

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Open Ended

What are your initial thoughts on the concern? Any test or inspections you would start with?

Ford Mustang Transmission Symptom Chart Link:

I will send it to you all now.

Look through this page and look for the symptom described by the customer.

3 Mins: Starting Now

Multiple Choice

What is the possible source of this concern based on the symptom chart?

• Normal Condition (Manual Transmission fluid is thick when cold)

• Internal Shift Mechanism

• Lubricant Issue

• Housing or shafts

When the transmission is cold the fluid is thicker and requires more effort to shift.

Let's do one more example

• 2015 Ford Mustang 5.0L MT

• The customer states there is a high-pitched whine or squeal coming from the transmission.

• The car has over 200k miles and has had regular transmission fluid changes.

Open Ended

What are your initial thoughts on the concern? Any tests or inspections you would like to start with?

First, look at the symptom chart and see if any of the symptoms listed match the concern described.

• Look under the NVH part of the symptom chart

• Noise Vibration and Harshness = NVH

Multiple Select

Select all of the possible causes below.

• Transmission gears are worn (high mileage vehicle)

• Mismatched gear sets

• Damaged or worn transmission bearing

• Axle howl or whine

• Worn countershaft gears

Multiple Choice

True or False: Since the concern is related to the internals of the transmission it must be removed and dissembled for proper inspection.

• True

• False

In order to inspect the transmission for damage, it must be disassembled.

Conclusion

There are several concerns related to transmissions and clutches best practice to start is to use a symptom chart and base diagnostic decisions on the chart.

Most faults will require the removal and disassembly of the transmission.

Extra Credit: Watch a manual transmission teardown video on YouTube (5 Points/One Assignment)

• Once you watch the video write one paragraph summarizing the video and information you learned.

• Good Example: https://www.youtube.com/watch?v=4cBKjbobwec