Results 1 to 20 of 21

Thread: Transmission (4L80E) First and Second Gear Only

Threaded View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Feb 2006
    Location
    Southborough, MA
    Posts
    6

    Red face Transmission (4L80E) First and Second Gear Only

    Hello,

    This is my first Diesel and my first Chevy Truck.

    My transmission only has First and Second Gear Only (no reverse, third or OD). I bought it this way, please don't ask why - I get enough grief from my wife.

    I've done a lot of searching on the web and have found conflicting info on the root cause and what the fix would be.

    I don't now very much about transmissions but my gut tells me that it is more likely an electronic or hydraulic problem rather than a catostrophic mechanical failure. But maybe this is just wishful thinking and am in denial about the possibility of replacing a sun gear, sun ring, sun shell, sprag or some other part requiring a rebuild (or close to it).

    I bought the ATSG (Automatic Transmission Service Group) manual "THM 4L80-E" for this transmission ($25 download PDF).

    In the troubleshooting charts they call out this specific condition "FIRST AND SECOND GEAR ONLY"

    INSPECT COMPONENT FOR CAUSE
    Solenoid B (311)
    Stuck Off
    Loose Connector
    No Voltage to solenoid
    Solenoid o-ring failure
    no PCM signal to solenoid

    2-3 Shift Valve Stuck

    Quad Driver Module Failed

    Possible Codes:
    68 Overdrive Ratio
    81 QDM & Solenoid B Fault
    85 Undefined Ratio
    87 Solenoid B Stuck Off


    I was getting a code 87 and quickly (maybe hastily) went and replaced the 2-3 Shift Solenoid. This did not fix it.

    While I was in there I should have checked the voltages to check for loose connecter, no voltage to solenoid and/or no PCM signal to solenoid.

    I also should have checked the 2-3 Shift Valve

    Does anybody know if I should see voltages if the truck is not running, but the ignition is in the "on" position and I put it in reverse or 3rd?

    Any experiences that you can share would be appreciated. I'll post back with my results.

    Thanks!

    Paul

    P.S. I bought a B&M Automatic Transimssion Drain Plug Kit #80250 to make future transmission fluid changes less of a hassle - in my opinion balancing a tray of hot tranny oil over your chest or face should be avoided

    P.S.S. I may have posted this in the wrong forum.... should it go in the "2500HD/3500 HD Trucks & Drivetrain" forum?
    Last edited by danbenili; 04-07-2006 at 07:33.
    '95 K2500 Extended Cab
    Mods: Pine tree air freshener
    Current Status: Lawn Ornament

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •