Here, I'll drag it a little off track again.....
We had only ran our JD770D about 50 hours, mostly pushing snow, when it had a glitch. Turned out to be operator stupidity more than anything else.
0200 a.m., zero degrees, six miles from the grader shed, pushing snow. I came to a T intersection, turned onto the cross road, shifted out of 6th forward and quickly into 4th reverse using the brake to stop. Very quickly shifted from 4th reverse to 4th forward. The machine went to 1st forward and started flashing a "check codes" signal. Hmmmmm,,,, what's going on?? I had the shifter in 4th fwd and the machine is idling along in 1st fwd with the indicator saying neutral. Hmmmm.... I clicked the shifter to 1st fwd and then back to 2nd fwd. Machine stayed in 1st fwd indicating neutral flashing check codes. Hmmmmm...... Now I'm a little worried, it's gonna be a long trip home in 1st. I'm afraid at first to do anything thinking it's gonna go to neutral and leave me stranded. After a few seconds I shifted to neutral and when the machine stopped moving I shifted to Park, then to 4th fwd. Again it went into 1st fwd. I stopped and shifted to 4th reverse and it went into 1st rvs. Now I'm really worried. I sat there for a few seconds analyzing what was going on. I didn't have the manual with me so couldn't look up the code, not sure it would have helped anyway. I had heard of problems with the Deere machines building up ice around the shift solenoids and causing problems. I got out and took a look. Couldn't see the transmission at all. Solid block of ice, hanging almost to the ground at the back of the machine. Bummer..... I called my Son out of bed, told him to stock up on ice chipping tools and head my way. I put the machine in 1st fwd and headed toward town. I hadn't went a mile when my Son showed up. We chipped ice away from the transmission until we could access all the solenoids. Everything was plugged in and looked fine. Him and I were standing in the middle of the road discussing our options. He is an automotive mechanic at a local dealership. He said "sometimes cars will do things like this and the computer won't reset without shutting down the machine and restarting. I moved the machine to the side of the road and shut it down. Waited a couple minutes and restarted. Everything was fine. No more problems and the code light went off. The next day I called the dealership and talked to the service manager. He said I went thru the shifter gate so quickly that the computer didn't keep up. He said they've had complaints of this problem before. The fix is to shut down the machine and restart. I later ran the code and that's the situation it described. The computer is designed to protect the transmission in every aspect. I shifted so quickly it didn't have time to diagnose what action I was requesting so it put itself in limp mode. Shutting off and restarting reset the computer. I love technology and would not want to move back to the old gear shifting transmissions of yesterday, but sometimes I just wish the computer would talk to me a little clearer so I understood what was going on. If I'd had my manual I probably could have figured it out. My bad.