4L80-E Archives - Page 2 of 2 - Transmission Digest
New Does Not Mean Good

As if the transmission industry weren’t difficult already, technicians also have to contend with new or remanufactured products that malfunction right out of the box.

Small Tips for Big Rebuilding Headaches Part 2

Many of you who call us for technical support and advice ask for items that fit this description. While we are always open to new ideas for new products that solve root-cause problems, there are times when these parts are already readily available and reasonably priced. It’s just that few rebuilders know about them. So, here are a few brief tips for you on some of the parts you asked for and where you can find them.

Fluid Change Can Cost Big Change ($)

Some of us may remember how in the days of old a C-6 transmission would leave a beautiful filter footprint in the bottom pan. This resulted from the filter opening being too close to the pan. When the pump started sucking, it would pull the pan right up to the filter, and as it vibrated away the filter etched itself into the pan. Of course, that starved the pump and caused premature failure of the transmission.

Out of Sight, Out of Mind

From time to time the ATSG tech line receives calls concerning 4L80-E transmissions with a reverse and/or third-gear problem. First thought may be compromised piston seals in the direct-clutch drum, or center-support rings. Perhaps even the center-support feed bolt is loose or cracked.

AFL and AFL

AFL stands for actuator feed limit and another fourth lost.

Perhaps you’ve already chased this on a 4L80-E or in a somewhat similar fashion on a 4L60-E. Here’s how badly it can go. You take in your buddy’s 4L80-E with converter codes and failsafe operation beginning to appear at normal mileage. Make it worse: It’s a good buddy, so you give him a break on the price. You scan the unit, drive it, do a careful rebuild, check TCC-related areas, put in a good converter, fill it with your preferred red fluid and reset the computer.

An Optical Illusion

There is nothing more frustrating for any technician and/or shop owner than to encounter a late-model vehicle experiencing problems and have no diagnostic codes to go by. One well-experienced example of this would be with pre-1996 vehicles. Many different styles of electronic transmissions would not set a code for an inhibitor switch because there were no codes for the computer to produce. So when it would malfunction, it would leave the technician clueless as to the source of the problem.

Low Line Pressure in 4L80-E in Diesel-Powered Trucks

Low Line Pressure in 4L80-E in Diesel-Powered Trucks

TASC Force Tips

Author: Gregg Nader, Sonnax