2010 3520 997 hrs Scary Shifting problem

[Beechboy]

Good day folks, got a really weird, and quite frankly , very Dangerous shifting problem on my tractor. Here is the sequence of events.
Started tractor this morning plus 10 C , light rain.
Drove the tractor across the farm for about 10 minutes. Shut it down to load a few timbers.
Started tractor back up, put it in reverse, no movement, put it in neutral , then shifted into forward , tractor took off in reverse.
Shifted into neutral then back into forward, tractor now moved forward as selected, but stopped on a dime after ten feet.
From then on stuck in neutral, forward or reverse selection made no difference.
Selected thru A B C no change. Put back in neutral and shut down tractor. Waited for a few minutes, started back up, put in forward and again tractor took off in reverse. While it was running I thought maybe the seat switch, pulled the Pto in ran fine no stalling. Deselected Pto , tried to drive, now wouldn't move at all for over 10 minutes. The hyd fluid is full and clean, changed at 800hrs.
This happened once before when it was new, was dumping a load of dirt over a cliff, selected reverse and tractor took off in forward. Just about drove over the cliff.
Caught my breath selected neutral then reverse, tractor backed up normally , turned around to head back to the house, when I selected forward, it jumped into reverse and tried to take me over the cliff in reverse this time. I locked the brakes and verified it was on forward!
Called JD service, they came out in a couple days jumped on and everything worked fine !!
Any ideas???
Still under extended warranty, and I am surprised that there is not a service bulletin out on this fault .

Anyone else ever have this problem , or hear of this problem???

Regards
Curtis
.

 

[deere5105]

Interesting and scary all at same time. Is this a Power Reverser transmission? Sounds electrical if I had to guess since turning machine off and back on sort of reset it. Will be curious to hear what you find to be the culprit.

 

[Beechboy]

Yup it is the power reverser transmission, that was my thinking as well, you can also sit there for over 5 or 10 minutes and shift from forward to neutral and into reverse and back again and it will not move. Thought it was the seat switch, but activating the Pto proved that the switch was ok. However turning off the ignition multiple times and back in sometimes works but not always.
Would love to get a diagram for the complete shifting and reverser system.