November 2003 Archives - Transmission Digest
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.

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.

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.

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).