Model 784 Rockshaft stuck in full up (transport) position

I can't believe I'm the ONLY one who ever experienced this concern - ONLY received one reply from JimB2 (thank you) on recommendation for investigation.
Briefly, I dead headed the MCV with a fixed load on the 3 point, shut off the tractor and freed the load after which the rockshaft went full up and does NOT respond to the position control lever.
I DID check all mechanical linkages underneath the rockshaft housing inspection cover and found NO issues. I can get the rockshaft to lower by pressing against the main are assembly (attached to the spool valve) which is part of the Draft Control Body Assembly (see photo). It appears this valve, for some reason which I and the dealer cannot determine, is getting powered at start up which raises the rockshaft. Moving the position control lever has NO effect.
The obvious fix is a time consuming/costly one involving removing fenders/fuel tank and the rockshaft housing exposing ALL of the mechanical and hydraulic systems underneath for investigation/repair.
I hold out hope that someone had this concern and could provide another answer (like draining Hytran, replacing it with kerosene then functioning the position control lever and, hopefully, eliminating a stuck valve).
ANY/ALL comments on above are appreciated.

Hi John, I posted a photo of the 74/84 hydraulic circuit that someone had posted on the Red Power forum. You can down load the
photo and expand it to view.
I assume you cleaned the Unloading valve in the Draft control unit.

Hope photo helps.
JimB

Draft lever is pushed all the way forward?

Position control doesn't work when the draft lever is pulled back all the way?

Thank You JimB2 for the IH Hydraulic System schematic. This helps me understand the circuitry better and (hopefully) diagnosing/repair of the Draft Control Cylinder and Valve underneath the housing cover (bummer).
Yes, I have taken apart/cleaned the Unloading and Flow Control Valve. Also the position of the Draft Control Lever has NO effect on rockshaft movement when the position control lever is actuated.

Had the same problem with 1086, not sure if set up same, but the draft control rod came loose inside rearend, had to pull third link plate off and reach in and hooked it back together. It was simple fix for that tractor. But I'm not sure if 784 if similar, but might be worth a try.

My service contact (Deryl Freeman, Alderman's in Lennon Mi.) says those tractors are completely different for those systems.

Deryl suggested another try to (hopefully) free up a possible stuck valve in Draft Control Cylinder and valve assembly (see pg 17, group 10 schematic in 784 Parts Catalog) by moving Main Valve Arm Assembly in or out by loosening the jam nut on the main valve actuator rod.

I will try this - anything to avoid having to remove the rockshaft housing (fenders, gas tank, etc.) which is an involved process to say the least.

(quoted from post at 07:12:22 09/07/18)
My service contact (Deryl Freeman, Alderman's in Lennon Mi.) says those tractors are completely different for those systems.

Deryl suggested another try to (hopefully) free up a possible stuck valve in Draft Control Cylinder and valve assembly (see pg 17, group 10 schematic in 784 Parts Catalog) by moving Main Valve Arm Assembly in or out by loosening the jam nut on the main valve actuator rod.

I will try this - anything to avoid having to remove the rockshaft housing (fenders, gas tank, etc.) which is an involved process to say the least.

Click to expand...

Did you ever figure anything out? I have a 684 that has a similar issue.