Page 1 of 2 12 LastLast
Results 1 to 10 of 14

Thread: auto transmission won't shift and rpm& speed guages don't work

  1. #1
    Junior Member
    Join Date
    Apr 2005
    Posts
    6

    Question auto transmission won't shift and rpm& speed guages don't work

    The two guages and the transmission not shifting by itself both stopped working at same time. I bought a new transmission three years ago never had any problems with it. I took truck into a good place to have it checked and was told its not the transmission but probably something to do with something in the electronics. He hooked up a computer to my truck just to see if it was reading a rpm signal. It did. It just was not reaching my my rpm gauge. So somehow the 2 gauges not working and the auto transmission not shifting are somehow connected somewhere I guess. I can still drive the truck but I have to manually shift from second to third to start or I just leave it in third. First gear and Drive don't work right now either. My wife was driving one time and she said the gauges all of a sudden started working for just a min and the truck auto shifted fine before it went back to not working. Does anyone know what is causing this? I've heard it could be the computer itself or something called a vulcan module ( i think that what it was called). Any ideas and if it is that module is it a fairly cheap item and where is it located?
    My truck is a 1995 gmc sierra 350 5.7L 4x4 1500

    Also I broke the door handle. where can I buy or do I have to go to dealer?
    Last edited by gmcer; 04-13-2005 at 12:53 AM. Reason: truck info

  2. #2
    Dax
    Dax is offline
    Senior Member Dax's Avatar
    Join Date
    Jan 2005
    Posts
    349
    I would try going to a junk yard first. We call them Pick&Pulls. It would be a lot cheaper and you could find that door handle.

  3. #3
    Senior Member mrjohnwayne's Avatar
    Join Date
    Apr 2005
    Location
    Texas
    Posts
    4,051
    If your truck is not starting out in 1st gear then quit driving it. Starting out in 2nd is a very good way to sending yourself straight to the shop. What year is the truck, and do you know what kinda tranny it is. 700-R4, 4L60E?? yes they are the same but they do have major differences.
    John Wayne

    2000 F-350 7.3L Powerstroke 4x4

  4. #4
    Full Member
    Join Date
    Feb 2005
    Posts
    33
    which guages are not working,if speedometer,replace speed senser on transfer case.

  5. #5
    Junior Member
    Join Date
    Apr 2005
    Posts
    6
    its the speedometer and the rpm gauge. would this sensor be causing the truck not to shift or start out in first? I can manually shift from 2nd to third but that's it.

  6. #6
    Full Member
    Join Date
    Feb 2005
    Posts
    33
    usually that is a A solenoid problem,but I have never seen a bad A solenoid cause the guage problem. The problem with the gauges could cause the shifting problem,and if I were to try to fix your truck if it came into my shop, first thing I would replace is the ingnition switch (under the dash),thats where we have found the most problem.

  7. #7
    Junior Member
    Join Date
    Apr 2005
    Posts
    6
    Ok, I'll Try Replacing The Ignition Switch And See What Happens. Where Is This Solenoid And Should I Replace It Too? I'll Hold Off On The Speed Sensor For Now. Probably Won't Need To Replace It.

  8. #8
    Senior Member Moostang's Avatar
    Join Date
    Apr 2005
    Location
    Cali-4 Nye-Aye?
    Posts
    1,832
    While you are under there, see if you are getting both power and ground to the guages I imagine you are not, then trace it back to where you get power.
    Rock, Paper, Scissors, Lizard, Spock

  9. #9
    Full Member
    Join Date
    Sep 2005
    Location
    georgia
    Posts
    11
    Id start by checking all fuses and the wiring harness going into the tranny. Check your battery terminalsare they clean and tight .
    Sounds like a bad earth wire or a loose wire or connector some where.
    With ign turned on i would feel around under dash checking/feeling wires and connectors while keeping an eye on the gauges. if the flash on its probably just a wiring connector loose. I have a feeling its a loose earth some where good luck hope this helps.

  10. #10
    Junior Member
    Join Date
    Jan 2006
    Posts
    2

    Angry Trans 4L80E concern

    I recently came across the same problem with a costumers Trans 1995 2500 chev 2WD 4L80E. Checked codes - converter clutch related concern?? Checked all-data info. TSB concern for vehicle was related to a EPROM udate. A concern with trans not shifting within 2 seconds of command . The new Eprom has a 4 second delay to allow for delay shift. I have not yet installed the new e-prom. Was going to check wiring due to the fact that when you clear the code the transmission shifts normal. When the Tach and speedometer start to drop or do not read is when the transmission goes into default mode and does not shift out of second gear . This a weird one . Have contacted GM - they have heard of trans concern - but not the gauge fluctuation concern. ???

    These electrical concerns can be frustrating

Page 1 of 2 12 LastLast

Posting Permissions

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