Click for JetForums Click for Lurssen Click for Ocean Alexander Click for Walker Click for Llebroc

Allison Transmission Pump

Discussion in 'Chris Craft Roamer Yacht' started by 67roamer, Jun 14, 2014.

You need to be registered and signed in to view this content.
  1. 67roamer

    67roamer New Member

    Joined:
    Jan 16, 2006
    Messages:
    13
    Location:
    Toronto
    We have a transmission running at 80 psi which should be around 120 - 140
    There is a nut on the side with a another nut inside with a spring
    Does anyone know if this is adjustable?
  2. Pascal

    Pascal Senior Member

    Joined:
    Feb 29, 2008
    Messages:
    5,636
    Location:
    Miami, FL
    Low pressure is usually a sign of low oil in those transmissions. Level needs to be checked with the engine at idle. Typically when it s low you will also get a delay in engaging in forward (reverse is not affected) then eventually if it gets too low you loose forward altogether
  3. Caltexflanc

    Caltexflanc Senior Member

    Joined:
    Sep 25, 2011
    Messages:
    244
    Location:
    North Carolina
    Like Pascal said, first make sure the oil level is right.

    Second, it depends on the pump, if it is a Hydreco, then yes it is adjustable. I never did it, am away from the manual so don't remember.

    I'd advise you call the nice folks at Acadian Transmission for advice on determining what you have and how to deal with it. They are the masters of al things Allison and related products. If the pump is bad, they are rebuildable.

    - Acadian Marine Transmission
  4. Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    8,974
    Location:
    Satsuma, FL
    Dont forget to check your screen, filter or any hose restrictions.
    I'm not an Alison jock, but the same theory of operation applies to all gears & clutches. Restrictions and air leaks will simply mess up a good clutch operation...
  5. Kafue

    Kafue Senior Member

    Joined:
    Nov 29, 2006
    Messages:
    1,150
    Location:
    Gold Coast Australia
    Brian Lemmon at Arcadian is a lot of help, even when you are on the other side of the world like I am.
    Hydrecos are quite easy to adjust. Pascal, Caltex and rccraps know the deal on these pumps and after 18 months of a lot of issues, I have learnt a bit as well.
    Check that screen.
    Check the oil while running.
  6. 67roamer

    67roamer New Member

    Joined:
    Jan 16, 2006
    Messages:
    13
    Location:
    Toronto
    Thank you for the replies
    Oil level is correct and screens are clean
    Will try the adjustment screw under the cap and report back
    Thanks again :)