Jerry Huerter, Author at Transmission Digest
Multiple Issues Demonstrate Need for Thorough Diagnosis

Our story begins with a 1995 Chevrolet K1500 with a 6.5-liter diesel and a 4L80 E transmission that was brought into our shop by one of our wholesale customers. The customer had replaced the transmission in this vehicle with one of our remanufactured units. After the installation, the customer said the check engine light came on and the vehicle was setting multiple transmission codes, and that when the truck was going around a left-hand turn the transmission would neutralize.

Information, Equipment & Experience

When a vehicle comes into your shop for repair you need to determine whether you have access to service information, the equipment needed to make the repair and the experience to repair it. As you read this article you will see just how challenging a transmission replacement sometimes can be. In this particular situation the service information was misleading and special equipment was needed to make the repair. This was one job that turned into yet another learning experience for me.

Understanding the AW 55-50 Neutral Control

A 2001 Volvo S60 come into or shop with a smoked AW 55-50 transmission that needed to be replaced.

The AW 55-50 transmission has a feature that Volvo calls “Neutral Control.” What is “Neutral Control” and what is its function? To tell you the truth, I wasn’t really sure, but below is what I was able to both find and figure out about it.

Shining Some Light on the Problem

A 1996 Nissan 300ZX came into the shop last summer. Remember, I said it was summer, which affects this story later.

The customer said the check engine light was on and that at times the transmission would not shift into fourth gear. I scanned the computer and found a P0705 inhibitor-switch code. I cleared the code and went for a test drive with the scan tool connected. Inhibitor-switch data was correct, and the code did not reset.