Hello all,

I'm investigating the source of some strange squealing noise on acceleration/deceleration. When I removed the drive belt to inspect the pumps/pulleys I noticed the ACE pump does not move freely at all - in fact it's quite hard to move it. Is this normal? I'm not sure if it's a hydraulic system or there should be a free spinning pump behind it?

Can anyone confirm if a functioning ACE pump /pulley should spin freely with the drive belt removed?

I found this similar thread but it went dead. https://www.landyzone.co.uk/land-rover/ace-pump.163407/#post-1619999

Thanks,
David

Hi. It's a radial 6 spring loaded piston pump so it doesnt spin free like a centrifugal one, you should feel the cam lobe pushing each piston as you turn the pulley

What belt do you have?

Try a genuine one.

The problem was ultimately the front prop shaft universal joints closest to the transfer case - they were almost worn through. Put a little bit of oil on them and the sound went away immediately. Will replace the joints asap.