# John Deere 2640 chattering hydraulics



## hawaiitractor (Dec 15, 2016)

I am working with a JD 2640 equipped with Front End Loader. Problem is that hydraulics chatter when I crack the loader valve - and when lowering the loader. What I mean by crack is that I just partially open the valve. If I open the loader valve all the way loader is smooth - no chatter, same with lowering. It is only at partial opening of loader valve that it chatters. Front pump pressure is good, transmission pump is new. Steering is excellant - not sure about Rockshaft yet - will check that tomorrow.

Does this sound familiar to anyone? Any advice / guidence would be greatly appreciated.

The loader valve inlet is plumbed from the pressure control valve (right side of transmission) to the loader valve through a quick coupler, probably old and well used - could this be the problem?

Thank you ahead of time.


----------



## BigT (Sep 15, 2014)

Hello hawaiitractor, welcome! 

Are you from Hawaii? If so, we can rule out a cold weather phenomena!

I suspect that a worn loader control valve can oscillate between open and closed when feathering (cracking open) the valve. 

The pressure control valve plumbed to the loader valve inlet can cause the same symptoms.


----------

