Wheel Loader FAQ

Case 821B LoaderQ: Why will my loader not engage forward or reverse?

A: 21 series loaders could have a number of problems which cause this issue these are –

  • electrical
  • hydraulic
  • mechanical


Most of the time the problem is with the electrical controlling of the transmission check –

  • declutch switch
  • transmission control relays / fuses
  • switches at the park brake or foot pedals
  • the FNR shift controller
  • coils in the transmission control valve
  • continuity of wiring to the control valve & grounding of wiring
  • Drain the oil into a clean container & look for any debris that would indicate a mechanical failure

A: W Series Loaders – Many models run air brakes & most have gear selection by mechanical cable
check –

  • air activated de-clutch cylinder located at the transmission control valve for rust / seizure
  • brake treadle valve sticking
  • selector cable condition
  • flexplate / convertor drive coupling for failure


If you need any other question answered regarding your Case Wheel Loader just leave a comment in the box at the bottom of the page & I’ll get back to you ASAP.

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5 thoughts on “Wheel Loader FAQ

  • G,Day Andrew
    You might know me as Queenslander on HEF
    Iam making a few enquiries on behalf of a mate who has problem with a 921D.
    After starting the loader and releasing the park brake the transmission will not engage, forward or reverse.
    Park brake appears to release, park brake switch tests OK, and two micro switches on brake pedal test OK.
    Trans. relay tests OK and when we ran a jumper lead to the circuit,
    trans. engaged normally, forward and reverse.
    Appears relay is not receiving power on signal circuit.
    Are there further limiting switches on this circuit?
    Owner says brake pedal feels doughy.
    Maybe accumulator pressure down?
    What do you think?
    Cheers, Greg

    • Hi Greg,
      I don’t get to see too many of those around here! For a certainty, the charge pressure needs to be checked to be sure you have the pressure required. I don’t have any of the specs for them, so you will need to verify with a CNH dealer.
      There are a couple of pressure operated de-clutch switches that should be tested, not 100% sure of precise location, but they should be in the articulation area.
      The EU Case parts catalogue doesn’t seem to be working ATM & the US doesn’t seem to list 921D. Looking at the 921C, the part number is L128914 & there are 2 of them – definitely test these also – if the D is the same??

      Sorry I can’t be more exact on a diagnosis, but I’m sure you can nut it out! 😉

  • Hi have a case721D wheeled loader ,used it, shut it down ,went to start it again, locked up, traced it to either transmission or hyd. pumps ,any thoughts.Thanking you.Keith.

    • Hello Keith,
      Sorry I can’t give you anything too specific on this, as I haven’t come across it before.
      I would look at the smaller brake pump on the engine before looking at the main hydraulic pump.
      Then it becomes a process of elimination with the main pump & then transmission.
      Maybe a good idea to drain your oils in the engine & transmission & see if anything comes out that shouldn’t.
      Hope this is of some help.

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