Tractor steering problem

I have an industrial tractor called a DO MOR, j d seller posted a pic of one like mine some time ago.
It is a componet tractor--Det.engine Napco heavy axles etc.
It has front wheel steer---all wheel steer and a position where all 4 wheels go sideways. The steering is controlled by a 3 way hyd. block to select the steering position.
I like to use it in 4 wheel steer---The PROBLEM---After using it for a day in 4 wheel steer the next time I start it up it will be in that crazy sideways mode with the rear wheels going sideways and the fronts trying to work somewhat normal.
I have to put the selector block in the sideways position -get the wheels straight then flip into 4 wheel steer----Sometimes it takes many times to get it working correctly.
I understand probably none of you are famaliar with a DO MOR , but hoping some might be able to explain the hydraulics. Thank you

ran into this same problem on a forklift with this style steering--the steer selector mode valve used magnetic coils to change functions. worked sometimes. bad coil. fell apart while changing, all burnt inside. quik fix after prob. was found, it slips over stem of valve assy-retained by one nut.

Your Do Mor tractor sound like it has the same steeting in it that the Case full 4WDs had in them 1200s late 60s thru 4994s late 80s which were discontinued when CaseIH bought Steiger Tractor.
The early models had mechanical cables and linkages that were connected to a hyd. control quadrant. all mechanical and front and rear axle cables went to a manual engauged selectable hydraulic lever to either move the rear axle steering equally in the 4 wheel steering mode, or by moving the console lever you could shift the lever to manually control the rear axle for two wheel steer or manually move the hyd control lever to crab the rear axle wheels.
There were some problems with cables streching and required ocasional adjustments.
Then they went to electronics over hydraulics. the cables were replaced by electric wires and position sensors were attached to the front and rear axle trunnions. A selector switch was placed in the console to elect to steer in 2 wheel mode, back wheels automatically centered, 4 wheel mode, called cordinated steer, where rears mirrored the fronts only in opposit direction, and then the crab steer mode that the operator turn the selector switch to crab, and could push a rocker switch to steer the rear axle independent of the front.
Sounds great, but that was when the electronic nightmares began.
The front axle steering was conventional hydrostatic steering, but the electronic sensors in the front dictated what the rest of the system did, and the didn't always comunicate properly.
Sounds like you are having one of the later night mares with a bad sensor, wirenig connection, ( continuity/ impedence) from point a,b, to selector, or the selector switch,
Good luck.
Loren, the Acg.

Thank you for the suggestions fellas--very much appreciated...