October 2005 Archives - Transmission Digest
A Primer on Proper Parting Procedures

When the first automatic transmissions were introduced in the late 1930s, the fluid coupling was routinely serviced as part of a transmission overhaul. The fluid coupling was bolted together, and servicing it didn’t require any skills that a regular mechanic wouldn’t have. When the fluid coupling evolved into the torque converter, it was still a bolt-together unit, and the only new challenge for the mechanic was to learn about stators.

Math for Mechanics

You can’t read or discuss anything about automobiles without getting into performance figures and estimates.

Don’t Let This Burst Your Bubble

The ZF 5HP19 FL/FLA automatic transaxle has had its share of problems during its tenure, fitted in the Audi A4, A6 and A8 and the Volkswagen Passat. One concern we have been dealing with recently on the tech line at ATSG is the complaint of neutralizing under a heavy throttle in first or second gear.

Stroke Choke

The forward-clutch control valve in the AX4N valve body (see Figure 1) plays a large role in the apply and release of the forward clutch (see Figure 2). The valve must be stroked or opened to allow pressure into the forward-clutch circuit to the shift valves and closed or unstroked to block pressure from the circuit.

That’s Gross!

Pricing jobs in the transmission- and auto-repair business has always been a complex issue. Coming up with a labor rate and a parts markup that make sense and are applicable in all situations is almost impossible. There are too many variables to consider.

October 2005 Issue

Issue Summary:

Before or after overhaul, vehicles equipped with the Chrysler 46RE may exhibit a recurring diagnostic trouble code P1740 (torque-converter-clutch or over-drive-solenoid performance) or P0740 (torque-converter slip).

Vehicles equipped with the 4F27E may exhibit a neutral condition in 4th gear after the transaxle reaches normal operating temperature.

Changes to the final-drive gears in the Ford 4F27E transaxle, beginning with December 2000 production, resulted in different gear ratios.

After overhaul, a Ford CD4E transaxle may generate code P0741 after the engine reaches operating temperature.

Reprogramming Our Procedures

We’ve heard many times how we can fix transmission problems by reprogramming the computer and how important it is to check for updates when dealing with a new problem or symptoms. Most of the technical-information sources have been preaching this for several years now, but it is important to note that you cannot rely on traditional service bulletins for complete information on vehicle-software updates.