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1994 Volvo A25C transmission hard shifting

Discussion in 'Other Earthmoving Equipment' started by BillyThePirate, Sep 7, 2018.

  1. BillyThePirate

    BillyThePirate Member

    Joined:
    Jul 21, 2017
    Messages:
    9
    Location:
    Montreal, Canada
    Hi everyone,
    I am having shifting issues with my A25 rock truck. What it does is that it upshifts and downshifts in every gear without slipping but it shifts so hard that it either swings me backward or forward in the seat. I'm sure I'll be due for back surgery if I don't fix this problem.
    I recently bought this truck and it had been sitting for a year. Did complete service and changed all oils and filters.
    I hope someone can give a hint as to what to look for.
    Thanks :))
     
  2. Mark250

    Mark250 Senior Member

    Joined:
    Aug 30, 2015
    Messages:
    761
    Occupation:
    heavy equipment technician
    Location:
    victoria,Australia
    Hi sometimes worn seat mounts worn cab mounts and worn articulation joints can give the impression of harsh shifting problems ,check these areas first.
    there are different versions of the A25C so a serial number will help give correct information ,for instance ther are different type of connections on the load sensor wiring.
    if you have access to the contronics service display you can check the operation of the load sensor on the display.
    If you have the overhead information display option ,are there any error codes shown?
    The easiest thing to check is the load sensor mounting ,adjustment and electrical condition as it is mounted on the fuel pump .This adjustment has an influence on the transmission modulating pressure ,which if incorrect can give harsh shifting and other problems
    here is a procedure to do a basic check on the load sensor

    upload_2018-9-8_7-54-31.png
    upload_2018-9-8_7-55-11.png
     
    Last edited: Sep 7, 2018
  3. Mark250

    Mark250 Senior Member

    Joined:
    Aug 30, 2015
    Messages:
    761
    Occupation:
    heavy equipment technician
    Location:
    victoria,Australia
  4. Mark250

    Mark250 Senior Member

    Joined:
    Aug 30, 2015
    Messages:
    761
    Occupation:
    heavy equipment technician
    Location:
    victoria,Australia
  5. BillyThePirate

    BillyThePirate Member

    Joined:
    Jul 21, 2017
    Messages:
    9
    Location:
    Montreal, Canada
    Mark250 Thank you so much, that is very good information and I will check that out as recommended.
    Working with it today I noticed that when I am pulling loaded the transmission shifts very well and softly, it is only when returning empty or downhill loaded when not in pull. This is a 1994, I dont have any electronic display.
    Serial number is : A25V8584