1. Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

Volvo A30C Transmission Problems

Discussion in 'Other Earthmoving Equipment' started by GYB, Nov 22, 2016.

  1. GYB

    GYB New Member

    Joined:
    Nov 22, 2016
    Messages:
    2
    Location:
    NC
    We have a A30C that shifts into reverse on start up. When you turn the key off, but do not kill the engine it relaxes back into neutral. Because of this we believe it to be an electrical issue. It will still operate normally, i.e. shift into forward gears. We found a bad solenoid in the transmission, but it still does it. We bypassed the ECU and it stops. After replacing the ECU it still does it. We have gone through all the harnesses & connections, we check the shifter. We have gone through every test in the repair manual. We just picked it up from Volvo after 2 months. They rebuilt 1 harness ordered a ECU from Sweden and exhausted all their options. Their next step was a $ 40,000.00 trans. We are at a brick wall and hoping some one has some advice. PLEASE!?!?
     
  2. Mark250

    Mark250 Senior Member

    Joined:
    Aug 30, 2015
    Messages:
    573
    Occupation:
    heavy equipment technician
    Location:
    victoria,Australia
    Hi GYB, i would suggest you need to work backwoods here and see what pressures are at the clutch stations
    For reverse to engage you need clutch K2 engaged and either brake B4 or B5 engaged depending whether in high or low.
    install gages in the ports shown and start machine, if there is pressure in K2 you have an hydraulic or electrical issue if you have no pressure and reverse still engages you probably have warped clutch plates in K2
    What was in the filters ? what was the lead up to the problem?
    shift matrix.jpg test points.jpg test pressures.jpg

    Mark
     
  3. GYB

    GYB New Member

    Joined:
    Nov 22, 2016
    Messages:
    2
    Location:
    NC
    Thanks for the response, Mark250. We will definitely try your suggestion. As far as the filters and the trans. (internal), everything was clean (very, very little metal, no more than normal wear and tear). The problem pretty much just happened over night. One day it was fine and the next it was trying to run in two gears. Thanks again.
     
  4. Bkish07

    Bkish07 Member

    Joined:
    Dec 21, 2016
    Messages:
    6
    Location:
    Michigan
    I had the same problem with the same machine in the end one of the clutch packs welded itself together. We did harnesses solenoids ECM the same stuff you have done and in the end it was the transmission needed a rebuild.
     
  5. Joe Walters

    Joe Walters Member

    Joined:
    Apr 4, 2017
    Messages:
    8
    Occupation:
    sales/service
    Location:
    Kansas City, Mo