ASE PREP: A2 Automatic Transmission Tips

ASE PREP: A2 Automatic Transmission Tips

Chances are you will not be rebuilding a transmission, but rather you will be listening to your customer's complaint and diagnosing it. Knowing where to start is the most challenging part of the job. The main focus of ASE's A2 test is the electromechanical part of the transmission. The basic concept to remember is that if the electromechanical part of the transmission not correctly controlling the mechanical components of the transmission, a mechanical failure will happen.


Chances are you will not be rebuilding a transmission, but rather you will be listening to your customer’s complaint and diagnosing it. Knowing where to start is the most challenging part of the job.

The main focus of ASE’s A2 test is the electromechanical part of the transmission. The basic concept to remember is that if the electromechanical part of the transmission not correctly controlling the mechanical components of the transmission, a mechanical failure will happen.

Inspection
If you are dealing with a failed transmission or a malfunctioning transmission that is slipping or has harsh shifts, pull the pan and examine the fluid. Any large metal pieces or a large volume of smaller particles attached to the magnet is a sign that a clutch or brake has been damaged.

It is critical to look at the condition of the fluid inside the transmission.

Meter Skills
Some transmission can have more than 10 shift solenoids that can generate a lot of codes for opens and shorts. The shift solenoids also have monitors that track the performance with pressure sensors and speed sensors. Some of these codes will guide you to a problem with a solenoid or the circuit.

There are two strategies when diagnosing solenoids. The first is to look at the circuit with a meter. The meter can display an open or a short in the circuit by just looking at resistance. But, this is only half of the story. Using a scope to graph the inputs and the outputs will let you see more of the story.

Some manufacturers include in their service information contains “known good” waveforms that even give instructions on scope setup.

Transmission Replacement
If the transmission is replaced with a rebuilt or remanufactured unit, there are three items that need special attention.

First, clean all transmission cooler lines and make sure no contaminants are left behind. Second, when refilling the transmission, use the correct transmission fluid that matches the transmission specification.

Third, after the transmission replacement, reflash the latest software to the ECM. OEMs will improve software to optimize shift quality and transmission component longevity.

You May Also Like

How Well Do You Know Your Driveshaft?

There are three types of modern driveshafts with multiple configurations.

What are the different driveshaft configurations?

• Single shaft with two Cardan universal joints;

• Single shaft with double Cardan on one end and one Cardan on the other end; or

• Split shaft with three Cardan and center carrier.

The world's longest one-piece light truck propshaft, brought about by a team of engineers from General Motors, Dana Corp, and Alcoa. Looking for a way to improve NVH on the Chevrolet Silverado and GMC Sierra
Heavy-Duty extended cab longbox pick-ups, engineers found the solution by replacing the two-piece steel design with a one-piece aluminum driveline. The team's challenge was to develop a one-piece aluminum propshaft with specifications previously unattainable in the light truck
industry.

Manual Transmission Service

Parts that wear out and must be replaced.

CV Axles: A Look Inside A Joint

Check out these photos and take a look inside a joint.

Transmission Valve Body Replacement Tips

Here are some important things to remember when replacing the transmission valve body.

Seven CV Joint Mistakes You Shouldn’t Make

If a CV joint fails, it rarely fails on its own. Outside factors can damage a joint worse than cutting a boot with a knife.

Other Posts

Fuel Pressure Diagnostic Service

Use a scan tool that can look at special direct fuel injection parameters and perform bidirectional tests.

Oversized Tires and Transmissions

Unfortunately, big tires go hand-in-hand with something less enjoyable: Transmission failure.

Reprogramming Today’s Transmission Control Modules

It’s understandable to have a lot of questions and fears about reprogramming. 

The Problem Is Not In The Transfer Case

The most important part of any repair work is locating the cause of the problem that causes the customer complaint.