1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

2000 Chevy 2500HD 6.0 4x4 Tranny Problem

Discussion in 'Chevy Trucks' started by chamonixvt, Dec 15, 2009.

  1. chamonixvt

    chamonixvt Junior Member
    from Vermont
    Messages: 9

    Hoping someone can point me in the right direction on how to trouble shoot a tranny problem.

    Transmission would not shift out of first gear which led me to believe it was in need of a rebuild/replacement. So, purchased a used tranny through a friend who owns a body shop, got it installed, new filter & fluid, and it still has the same problem, it won't shift out of first gear. My buddy at the body shop is telling me it is an electrical problem

    Before potentially spending a lot of money with a tranny mechanic trying to figure out what is wrong, I thought I'd see if anyone out there might have an idea or suggestion or experience?

    In the end, I'm likely heading to a tranny mechanic but I thought I'd give this a try.....

    Thanks
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Very likely an electrical issue, especially considering you changed the entire trans.

    When a 4L80E gets stuck in first only it's usually do to a broken/damaged wire to either the input or output speed sensor, or a bad sensor if you swapped them from the old trans. Need to check the wires with an OHM meter and the sensors too. Your trans shop can do these checks for you for minimal cost.
     
  3. chamonixvt

    chamonixvt Junior Member
    from Vermont
    Messages: 9

    thanks for pointing me in the right direction. In the course of tracking down this problem we came across the neutral safety switch which had two of the connections melted. Could this be the cause of the tranny not shifting or do we need to continue searching? We have not put in the new switch yet, just got it today from the dealer.

    Any help would be appreciated.
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Melted connectors? As in from excessive heat?
     
  5. chamonixvt

    chamonixvt Junior Member
    from Vermont
    Messages: 9

    appears to be the case - excessive heat that is..
     
  6. chamonixvt

    chamonixvt Junior Member
    from Vermont
    Messages: 9

    if it is from excessive heat, any idea what could have caused this? I'm at a loss.
     
  7. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Are the connectors melted, or does it look there is glue type stuff all over them? Can you post a pic?
     
  8. chamonixvt

    chamonixvt Junior Member
    from Vermont
    Messages: 9

    My buddy and I both agree, melted as they are disfigured. Will try and post a pic tomorrow.

    Like the quote about change in your post - quite accurate.
     
  9. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If they're actually melted then replace the connectors along with the switch. Connectors can be purchased as pigtails from the dealer. Not inexpensive, but available.
     
  10. chamonixvt

    chamonixvt Junior Member
    from Vermont
    Messages: 9

    Got the switch and connectors from the dealer just haven't had a chance to work on it as my buddy who has the skills works for a ski resort in their maintenance shop - planning on replacing today. I'm just an extra set of hands and a source of information through this site - which has been extremely helpful and saved a fair amount of time.

    Do you think this is the cause of the shifting problem? Also, any idea how these could have melted?
     
  11. GLSCPE

    GLSCPE Junior Member
    Messages: 13

    LOL this is such an issue with these trucks!! I have replaced Neutral Safety Switches twice in three years on my Duramax/Allison. They get trashed, and start throwing range shift inhibited errors, and wont drop into any gear. When they work they are great, but it is a common problem!
     
  12. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Excessive resistance in the connectors due to corrosion on the connectors or the switch itself are a contributor. Tapping in extra reverse lights into the stock reverse light circuit without using a relay to carry the extra load is the #1 killer.
     
  13. Sydenstricker Landscaping

    Sydenstricker Landscaping PlowSite Veteran
    Messages: 3,882

    Shyt better get mine on a separate wire harness with a switch then, lol
     
  14. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    You won't be LOLing when you price those pigtails :laughing:

    Nothing wrong with using the reverse lights for the "switch" just use a relay and pickup power from the trailer charge wire.