April 2007 Archives - Transmission Digest
Searching for Identity

Identification of the vehicle and unit you are working on is the beginning of doing the job correctly. It is getting increasingly difficult to obtain the correct information and even to locate a service manual or Internet site.

Lockup Surge in Allison 1000s

Have you ever found yourself chasing a “phantom” TCC drivability problem in a GM vehicle that uses the Allison 1000/2000/2400 series of transmissions?

If you have, there’s a good chance that the root of your problem turned out to be the torque converter. No earth-shattering news there, but what is unique is that the problem was likely on the outside of the converter, not the inside.

April 2007 Issue

Issue Summary:

After overhaul, vehicles equipped with the Ford 5R55N may exhibit a soft or flared upshift into 3rd gear.

Vehicles equipped with the Chrysler 45RFE may exhibit a slip on take-off or no movement after overhaul or fluid change.

Corroded terminals in the PCM connectors can cause failsafe in a 1998 or later Dodge truck with Cummins diesel engine, resulting in 3rd-gear starts.

Small-Business Owners May Be the Most Gullible People in the World!

When you own and operate a small business of any kind, especially one as challenging as automotive, you’d like to think that there is a magic answer to all your problems, especially the financial ones. Whenever a large group of people is that desperate to find a solution, you can bet that at least a handful of ne’er-do-wells will come along to claim that they know what it is. They always make the answer seem simple, but it usually turns out to be quite expensive and sometimes overwhelming to implement or maintain, if indeed it works at all.

Catching a Brake on Shift Problems

A 2001 Nissan Altima was brought to a transmission shop with the complaint that the shifter would not move into reverse or park. The customer explained that the vehicle performed just fine when cold but occasionally refused to go into reverse or park after warming up. The shop performed its routine pre-checks and then road-tested the vehicle. The pre-checks didn’t show any codes present (not even a history code), and the technician wasn’t able to reproduce the condition on the road test. The customer was asked to leave the vehicle for further evaluation.

The Bucking Audi

The continuously variable transmission (CVT) used in Audi’s A4 and A6 vehicles, called the 01J or Multitronic, could show up in your shop with a bucking complaint. This style of CVT (see Figure 1) does not use a fluid coupling as a pass-through device for engine torque input. This means that when the vehicle is engaged or comes to a stop in gear, the forward or reverse clutch must slip. When the brake is released and the throttle is depressed, the clutch applies and the drive and driven pulleys begin to move in relation to each other to provide gear ratios.

Things Aren’t Always What They Appear to Be

Things aren’t always what they appear to be; at least, that was the case concerning a call we had on a 50-42 LE unit in a Volvo with good forward gears and a slipping reverse before rebuild. It was one of those used-car-lot customers that didn’t want to spend any money but wanted a lifetime warranty. I am sure you know what I am talking about.