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Here is a compiled listing of the most popular topics discussed here at DieselPlace.com under the 4L80E/4L60E Forum. This is to help you speedily find your answers, without having to wait for a reply to your question. We love to answer questions, and enjoy gathering around the computer to help others out. We’ve all been there. This forum is a living library of information.

Click on the solid underlined word of any topic of interest and it will hyperlink you to the area in the forum where the information was first posted, for example if you click on the underlined word(s) for any topic, this will take you to the thread with information about the topic.

If you don’t find a topic listed, feel free to do a search. You may have to do an individual word or a phrase search, as with any search engine you may need to be creative in describing what you are looking for, don't give up if first search you type comes back with nothing found, there is a entire forum search, & search within a forum sub group, author, subject, date. It may be worth your while to read all FAQ topics 1st so you can inject words or phrases common to the GM 4L80E to help with your searches.

Building the 4L80E FAQ library - If you see a topic that you want to add or think should be added, please paste a link in a PM to Diaric or Freddyack.

Thanks and enjoy!
The Diesel Place Staff

Component/System & What Each Affects - For more information Click Here

4L80E Model Year Differences - Explanation of changes to the 4L80E by model year Here

Basic Trouble Shooting:

1. Mechanical vs Electrical Problem - First determine if the problem is mechanical or electrical. Here is how to do this

2. Harsh Shifting/No Up Shifting Into Overdrive - One of the largest concerns frequently mentioned is the dreaded harsh shifting and no up shifting into Overdrive. For trouble shooting information Click Here

Manuals These manuals are .pdf files which will download to your computer when you click on the link:

4L80E Automatic Transmission Rebuild Manual Here

4L80E Transmission Electrical Supplement (GM) Here

4L60E Automatic Transmission Rebuild Manual Here

1994 Transmission Manual: Here

1995 Transmission Manual: Here

1996 Transmission Manual:
  • 4L60E and 4L80E Service Manual Here
  • 4L60E and 4L80E Diagnostic Manual (Includes DTC Codes) Here
1997 Transmission Manual:
  • 4L60E and 4L80E Service Manual Here
  • 4L60E and 4L80E Diagnostic Manual (Includes DTC Codes) Here
1998 Transmission Manual:
  • Contents Here
  • 4L60E and 4L80E Manual Here
1999 Transmission Manual:
  • Contents Here
  • 4L60E and 4L80E Manual Here
Technical Videos


4L60 Transmission Cooler Upgrade Click Here

Stand Alone Transmission Controller How to build your own Stand Alone Transmission Controller Click Here

Temperature Gauge
Torque Converter (TCC) Manual Lock Up
Parts List Click Here



2 - Second Gear Only Condition - See VSS below Or Click



  • Electrical - See Electrical - 4WD
  • Transfer Case - See Transfer Case



Block Diagram 4L80E Transmission - Click Here

Cooler Line Leaks - How to repair transmission cooler line leaks Click Here

Component Slipping - Click Here

Connector Test Points - Transmission connector test point pin locations and what they are for iincluding diagrams and pictures Click Here

Coolant/Moisture In Fluid - Click Here



Electrical - 4WD

Electrical Component Diagnosis Information - This helps to spell out better the solenoid's roles and electrical/sensor responsibilities in the system. Click Here

Electrical Connection Test Cable Click Here

Filter - Remote Transmission Fluid Filter See "Remote Transmission Fluid Filter"

4L80E Fluid Change How to do a complete fluid flush Click Here

Gear Ratio Errors DTC Codes: 85, 86, 87 - What to do if you have these codes Here.


High Line Pressure causes hard shifts - There are two areas to check: Electrical and Mechanical/Hydraulic. See this reference Click Here





Line Pressure - Transmission Line Pressure - Click Herefor the internal operating conditions.

Low Voltage at Pin E - Verify voltage like this poster ran into. 4L80E Electrical ? 2nd gear only :( - Page 3 - Diesel Place : Chevrolet and GMC Diesel Truck Forums Post #22.


Manual Shift Only - All Gears Work: Click Here



OBDI DTC Codes: Click Here

Overdrive - Click Here


Painless Transmission Controller Documentation This is a .pdf file that will download to your computer when you click on the link Click Here

Pan Bolt Torque - Transmission pan torque specs:

Passthrough Connector - The pins and where they go Click Here

Pressure Control Solenoid (EPC) Test Points at Passthrough Connector - Click Here


Range Pressure Switch (DTC Code 28 Transmission range pressure circuit fault) - Click Here

Remote Transmission Fluid Filter

  • Why not to install a remote transmission filter Read This
  • If you want to install a remote transmission filter: Read This
Remove/Reinstall - Tips and Tricks Click Here

Reverse Problems
Reverse (Binding In Reverse) - Is there something specific that causes N to be a drive gear? Usually when I experience a bind up in reverse, it is because the forward clutches failed. The forward clutch is on in all forward gears only. When the forward clutches fail they go metal to metal and what you have is too much clearance in the drum causing the forward apply piston to come out of its bore. When this happens, the forward apply piston will not return to the release position and the clutches stay applied no matter what gear you put it in including reverse or neutral.


Sensor and Solenoid resistance table - Click Here.

Shifter - How to fix loose shifter Click Here

Solenoid Locations Picture - Click Here

Solenoid Electrical/Wiring Chart - Click Here

Solenoid Schematics/Wiring - Click Here

Shop Selection/Inspection - Find a transmission shop with the ATRA Logo. Additional information on how to find a good transmission shop Click Here

Speed Sensors - Input and Output - Click Here

TISS - Transmission input speed sensor

TCC - Torque Converter Clutch - the clutch that locks the tranny instead of passing engine torque through the torque converter. This reduces heat in the transmission and improves fuel economy similiar to a manual transmission. Picture Click Here

Torque Converter Clutch (TCC) - Not Engaging? Click Herefor details.

Torque Converter Clutch Solenoid - Here. How it works Click Here

Torque Converter Shudder: Click Here

TCM Wiring Diagrams - can be found Click Here

Throttle Position Sensor - Mechanical IP - Click Here

TOSS - Transmission output speed sensor

Transfer Case - 4WD

Transmission Fluid Temperature Sensor -
Turbine - Here



VSS - Vehicle speed Sensor - Click Here

VSS Buffers This is a .pdf file that will download to your computer when you click on the link Click Here

Wiring Diagrams



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