Results 1 to 5 of 5

Thread: Source of data on GM.GEAR PID

  1. #1
    Junior Member SirNemesis's Avatar
    Join Date
    Dec 2007
    Posts
    24

    Default Source of data on GM.GEAR PID

    Hi guys,

    I'm in the process of troubleshooting a shifting problem with my project car and knowing the source of data for the GM.GEAR PID will greatly assist with the troubleshooting process.

    Summary:

    Gen3 6.0 Volvo 240. Running cable throttle and flex sensor
    4L80e, rebuilt by me
    Whole car rewired by me
    P59 PCM running 03150003 OS with 4L80e segment swap

    I have mentioned 'by me' so people can safely assume I don't know what I'm doing and can also identify things I've likely screwed up.

    The problem I'm having is with 2nd gear. It doesn't seem to exist for automatic upshift or automatic downshift, yet everything else in the transmission works nicely (including manual 2nd). I'm logging GM.GEAR and can see in the logs it shows 2, but it doesn't 'feel' like its getting 2.

    If I can confirm where this information is source (e.g. requested gear from PCM, OR feedback from transmission pillow switches to indicate shift selection), I can potentially rule out a bunch of areas I've played with (or not).
    1985 Volvo 240 || LS2 || 4L80e || S488 Turbo

  2. #2
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    You should see engine rpm and vehicle speed correspond correctly...

    Post tune and logs.

  3. #3
    Junior Member SirNemesis's Avatar
    Join Date
    Dec 2007
    Posts
    24

    Default

    Quote Originally Posted by joecar View Post
    You should see engine rpm and vehicle speed correspond correctly...

    Post tune and logs.
    If only it was that easy to tell...

    - I've never driven a car with a stall
    - I've never driven a car with a 4L80e (different gear ratios to a 4L60e)
    - Engine is loud

    I believe I've found the source of the problem, but for the purpose of closing out this question lets keep the discussion going. While I was unclear/unsure of it before, it is pretty safe to say that I do NOT have 2nd gear in the log attached.

    Log file and tune attached.

    Log_0001.efi
    AZ_COS3_V60_FX_4L80E_12579405-V2P12.ctz
    1985 Volvo 240 || LS2 || 4L80e || S488 Turbo

  4. #4
    Lifetime Member
    Join Date
    Jul 2003
    Posts
    1,897

    Default

    There is a parameter to set the current gear based on the pressure control solenoid inside the trans. Set the PRNDL to none IIRC.
    "All that is needed for the triumph of evil is that good men do nothing..."

  5. #5
    Junior Member SirNemesis's Avatar
    Join Date
    Dec 2007
    Posts
    24

    Default

    While I'm still chasing confirmation, I believe the data output of GM.GEAR is actually the requested gear position from the PCM without any feedback from the pillow switches inside the transmission at all. The reason I was missing 2nd gear was a physically missing lip seal which would apply 2nd gear in the transmission. While I don't believe there would've actually been enough pressure under the pillow switch to apply this button, it would have helped with my troubleshooting before pulling the transmission out.
    1985 Volvo 240 || LS2 || 4L80e || S488 Turbo

Similar Threads

  1. Source and target (PID) addresses
    By TomStillo in forum General
    Replies: 4
    Last Post: September 24th, 2014, 12:59 PM
  2. witch pid for m6 gear box with E38
    By restless@westnet.com.au in forum General
    Replies: 2
    Last Post: June 5th, 2011, 01:57 PM
  3. GM GEAR pid unable to validate,
    By alian in forum FlashScan V2
    Replies: 4
    Last Post: September 22nd, 2008, 09:19 PM
  4. Do I need a PID to LOG serial data?
    By Chalky in forum FlashScan V2 BB Logging
    Replies: 1
    Last Post: May 15th, 2008, 10:16 PM
  5. M6 (Tremec T56) Gear PID?
    By Tordne in forum General
    Replies: 31
    Last Post: July 27th, 2005, 02:08 PM

Posting Permissions

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