2003 Archives - Transmission Digest
Rich History – Bright Future

Transmission Digest visits ATSG to discover how the company links tradition with forward thinking.

Micro Cleaning

Cleaning’s not technical, right? You take a little soap and water and scrub and wash, scrub and wash some more, rinse, and the part’s clean. Or maybe you use some solvent, different chemical cleaners to get the really hard stuff and get it looking like new, so clean you can eat from it.

Clutch Technology – the Real Deal

One of the most-common repairs performed by transmission and general-repair shops is clutch replacement. The clutch is a high-wear item that must engage and disengage hundreds of times a day. It is subject to a lot of driver abuse; vehicle overloading; wear and failure of linkage, hydraulics and powertrain mounts; and contamination from oil leaks in the engine or transmission.

December 2003 Issue

Issue Summary:

Beginning with the 2001 model year, all 4L60-E transmissions were produced with a new-design converter-clutch regulator-valve lineup in the valve body.

2000-model GM trucks equipped with 4L60-E transmissions and either 4.8- or 5.3-liter engines may experience a driveline vibration at speeds between 35 and 50 mph during conditions of low engine speed and the driver’s foot off the accelerator pedal.

The valve-body spacer plate for the 4L60-E transmission has changed every year since its introduction in 1993, and the plates will not interchange from year to year. The valve-body casting changed again for model year 2001.

Some 1999-2001 Chevrolet and GMC C/K trucks and/or Cadillac Escalades with 4.3-, 4.8-, 5.3- or 6.0-liter engines and 4L60-E or 4L80-E transmissions may, on initial startup during cold weather, exhibit late 2-3 and 3-4 shifts and delayed converter-clutch application.

A Case of a Leaking Capacitor

It is not uncommon to hear of a technician investigating the inside of a computer as part of a diagnostic routine, especially when dealing with odd continual electrical problems.

Sometimes when the box is opened, a distinct burnt odor confirms the technician’s hunch that it was fried “Fred” causing the problem all along. Sometimes a cracked circuit board is the cause of those pesky intermittent trouble codes. On other occasions the box is filled with water from a leaking sunroof (Honda/Acura) or a leaking heater core (Mitsubishi/Hyundai), or it just had the misfortune of being in a flood.


The title of this article envisions scenes from that 1950s “B” sci-fi movie by the same name – only, in this instance, “THEM” refers to the original-equipment manufacturers. This month I have a few tidbits relating to problems you may have to deal with that were created by the vehicle manufacturers.

Domestic-Truck Transmission Identification Guide

One of the difficult problems facing most transmission shops is the identification of manual transmissions. To be able to order parts and create a valid sales quote for a customer, the shops have to know what they are working on. Stick-shift transmissions comprise about 20% of the market; so most shops are very familiar with automatic units and have difficulty with manual-trans identification. The following guide provides some basic information to lead you in the right direction as to which transmission you are working on. Space limitations do not allow us to list every manual transmission you may encounter, but those listed here are the most-common units in domestic trucks and sport/utility vehicles.

Transmission Coolers, Part 2

Auxiliary coolers have been available for almost as long as automatic transmissions have. For many of us who have been around a while, most auxiliary coolers were used to supplement the factory transmission cooler for towing or other heavy-duty purposes. In the TASC Force Tips article “Contamination and Coolers” in the August issue, we discussed the need to replace some coolers, but I realized that there are no guidelines for choosing the right-size cooler to install.

Montero Madness

There have been an increasing number of calls lately concerning manual code retrieval on Mitsubishi Montero models equipped with the R4A/V4A51 transmission.

The nature of the problem seems to involve the blowing of a fuse in the underhood fuse box when pin 1 of the OBD-II diagnostic connector is grounded.

November 2003 Issue

Issue Summary:

After re-installation, the transmission in a Nissan Quest/Mercury Villager is stuck in third gear, line pressure is at a maximum level and the inhibitor-switch circuits do not range correctly. Solenoid codes also may be present.

The Audi 01F/01K transaxle (ZF 4HP-18FLE/FLA) may have a vent cap mounted on top of the transmission filler tube instead of a dipstick.

In GM electronically controlled transmissions, false output signals can cause complaints including no TCC apply, wrong-gear start, missing gears, falling out of gear, or line-pressure control problems.

When removing the allen-style torque-converter bolts in 4L60-E and 4L80-E transmissions, a technician may find them difficult to remove and possibly round out the internal hex slots.

1999-2002 4WD trucks with a New Venture Gear 236/246 transfer case may experience a “Service 4WD” indicator light that remains on, possibly accompanied by Service Code B2725 (ATC Mode Switch Circuit Malfunction).

An electronically shifted GM transmission may exhibit late 2-3 and 3-4 shifts under heavy-throttle conditions but seem to operate properly under normal throttle conditions. It also may have an elongated forced detent shift with no increase in vehicle speed that may require the driver to back off the throttle to complete the shift.

No Vehicle-Speed Sensor?

A 1995 Lincoln Continental with an AX4N transmission comes into the shop with a gear-ratio-error code. As you are going through the diagnostic routine, you have pretty much determined that the unit needs to come out. But before you remove it, you decide to check for a glitch in the vehicle-speed sensor (VSS).

Getting Polished With Chrysler’s Buffer

The speed buffer in a GM vehicle (see Figure 1) is a familiar piece of hardware for most transmission technicians. And its operation of taking an AC voltage signal from a speed sensor and converting it to a DC pulse signal for the computer is just as familiar. But what does come as a surprise to many is that Chrysler uses a similar speed-signal strategy for many of its passenger cars and vans.