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

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  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

  2. #2
    Join Date
    Jan 2005
    Posts
    479

    Default

    I've OH'ed lots of slushboxes, but never a 4L80E.

    A guy that rents property from me has a 1994 with the exact symptoms your's has.

    We have not torn into it, yet, but from what I have been reading, the "no reverse" is a "red flag" for a "hard parts" failure, rather than an electrical or solenoid failure.

    Reverse is supposedly all mechanically selected by the manual valve, and (except for pressure control), shouldn't suffer from a 'puter, wiring, or solenoid problem. It is likely the problem is in the DIRECT clutch, or associated sprag.

    I'd be curious as to what you find out, if you get into yours in the near future, as it will be a while before the one we're dealing with gets checked out.

  3. #3
    Join Date
    Sep 2000
    Location
    Imperial (St. Louis), Missouri
    Posts
    698

    Default

    I had the same problem. No shift out of first till a very high rpm, then a slam-shift to second, and nothing else. My speedo went nuts as well.

    It turned out to be a faulty output shaft speed sensor. there are two shaft speed sensors, one for input, one for output, and the computer uses them to determine clutch slippage. if one dies, the computer sees it, and forces a 'limp-home' mode. I dont think it lights the SES when it happens.

    The sensors are like $40 at autozone, and its a 5 minute deal to change them.

    Tim
    Ford Owner.


    Music by Andrew Lloyd Weber. Lyrics by Andrew Dice Clay

  4. #4
    Join Date
    Feb 2006
    Location
    Southborough, MA
    Posts
    6

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    Hi Tim,

    My symptoms are a little different - no slamming etc. It drives normally but without reverse and won't shift into 3rd. It does sound like the sensors could be the culprit.

    Did you have reverse?

    Paul
    '95 K2500 Extended Cab
    Mods: Pine tree air freshener
    Current Status: Lawn Ornament

  5. #5
    Join Date
    Sep 2000
    Location
    Imperial (St. Louis), Missouri
    Posts
    698

    Default

    Quote Originally Posted by danbenili
    Hi Tim,

    My symptoms are a little different - no slamming etc. It drives normally but without reverse and won't shift into 3rd. It does sound like the sensors could be the culprit.

    Did you have reverse?

    Paul
    Yeah, I did, now that you mention it...

    Still and all, its probably a good thing to take them out and at least check them. I checked resisiance through both of them and found them vastly different. I cant remember what the resistance of the good unit was.

    tim
    Ford Owner.


    Music by Andrew Lloyd Weber. Lyrics by Andrew Dice Clay

  6. #6
    Join Date
    Jan 2001
    Location
    New Hampshire - Live Free or Die
    Posts
    6,057

    Default

    I'm voting with BobND. Reverse is purely mechanical, so no reverse is a mechanical problem.

    First check for codes, but I'm betting you're in for some hard parts.

    (sorry...)
    The Constitution needs to be re-read, not re-written!

    If you can't handle Dr. Seuss, how will you handle real life?

    Current oil burners: MB GLK250 BlueTEC, John Deere X758
    New ride: MB GLS450 - most stately
    Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510

  7. #7
    16gaSxS is offline Moderator, Have Shotgun & dogs will travel
    Join Date
    May 2002
    Location
    Great Falls, MT
    Posts
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    I'm with Bob, I had a 2 gear and reverse ok problem it drove me nuts it was something electrical , poor connection or short the exact problem was never found after much work it just went away. If you have a electriconic problem you go 2 nd gear only as a default. You can work through your codes. There are a number of componets that are can be changed if you drop the pan. If you change them all out it will cost serveral hundred dollars. (been there done it). If you have a honest and good transmission sho they maybe able to help. A local sho the owner check mine and drove it twice and he told me it was the electronics. Good luck keep us posted maybe someone that know these trannies can help you more.
    95, 6.5, C-2500 extended cab shortbox, Auto transmixer 3.42 diff, Jardine exhaust system
    FSD Cooler replaced w/ Heath PMD Isolator
    Heath Turbo-Master Boost Controller, Max E Tork chip '97 cooling upgrades, Kennedy Fan clutch,
    Glow Plug over ride,DeeZee 38.5 gallon Aux fuel Tank 225K miles and rolling

    1994, 6.5 Blazer, 3:42 diff, 4 inch exhaust, Heath PMD Isolator, Heath Turbo-Master Boost Controller Max E Tork, Heath SB intake filter system.
    221K miles and rolling.
    Diesel Page member #81

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