JD 8640 hydraulic problems

[xx507xx]

hey guys need some help i have an 8640 that lost all hydraulics i have checked the two screens on the back half they were clean and the coupler from the engine to pump is good i have no steering or remotes
thanks Errol

[buickanddeere]

If equipped with a pto, does it work? Is the trans hydraulic circuit maintaining 165psi? Could be a failed trans pump or trans pump drive. On occasion the pressure relief or the plugged filter divert valve will stick with a wee bit of dirt or a broken spring. No oil from the transmission hydraulics pumped up to the front pump inlet means no high pressure hydraulics.

[xx507xx]

pto works. i will check thoues out 2marrow thanks

[Tx Jim]

Non functioning stroke control valve in main hyd pump will stop hyds from working