John Deere JD 400 tractor hydraulic problem

[freddmc1]

I have a 1973 John Deere JD 400 tractor with a bucket where the bucket raises very slowly chattering all the way up. It usually doesn’t happen if the bucket is empty but if there’s any load at all bucket just shakes as it’s going up, any ideas would be appreciated.

 

[Tx Jim]

Welcome to this forum
How many hrs of use since hyd filters were changed & hyd oil suction screen checked/cleaned? Next I recommend checking hyd stand-by pressure by attaching a hyd gauge to RH front side of front hyd pump. Stand-by pressure should be 2250-23350 psi.

 

[TomBexley]

Along with the filter, suction screen and standby-pressure checks Jim mentioned, I'd pay attention to whether anything else hydraulic changes while the loader is chattering. Does the steering feel different at the same time, or is it only the boom circuit? I'd also check the oil level before doing much else and look at the oil after you've operated it. If it's getting foamy or full of tiny bubbles, that seems like a useful clue that the pump may not be getting a clean supply of oil rather than the problem being only in the loader cylinders or valve. Don't start replacing loader parts until those basic supply-side checks are done.