Before taking it to the shop, I disconnected the sensor on the diff. I then drove it down the street and measured the speed with a gps phone app. It stayed in only one gear (probably 1st) and it went 19 miles an hour without the violent shutdown that it does with the speedometer wires plugged in.
I believe the P, R, N and front diff lock lights work correctly.
There is one more thing. I replaced the rear diff as soon as I purchased the SXS. It was not running when I purchased it so I don't really know if changing the diff has anything to do with its current condition.
Was this machine beat up when you got it?
Can you put up a video of what it's doing?
Does this seem like a rev/speed limiter, or is the machine just bogging...like if you had hit the brakes? Is the engine winding out when this happens, or at a relatively low RPM?
The D, N, and R indicator all match the dash markings?
I'm trying to think of rev/speed limiters present on the 700. I believe there's one in reverse, but I don't know what speed that is. There's also one present if you use the start-in-gear feature, But that one is literally just off idle. Don't know if you could even get 12mph out of that.
I don't think there's one for diff lock or the parking brake being on. And of course there's a seatbelt that's always been mentioned 50 times, but doesn't apply to your machine.
If you do a little searching online you can find a service manual online in PDF form. It's available here for paid members, or
@BobRack might get you one as well. I don't know if it's even feasible or possible that the connectors and/or solenoids for the valve body on the tranny somehow got reversed. The emergency valve you screwed locks the machine second gear and bypasses all electronic controls.
Again, a little video clip of what it's doing would be very helpful?