3 pedal autoshift

I'm having an issue with my autoshift transmission. It's in a 2013 KW W900.
I had the truck in the shop getting the fuel pump done. When the mechanic went to pull it out of the shop and take it for a test spin...the trans was throwing a bunch of codes. It wouldn't go past 10th gear and would only go up to 10th two gears at a time. I got to the shop and took it out also. It was throwing codes for range valve, splitter valve, speed sensor, road speed.
So back in the shop, I pulled the fuse, erased the inactive codes and he was underneath and tapped on a couple sensors and pushed wiring plugs in tight.
Took it back out and it worked perfectly.
My driver took it out the next day and it works good til 10th then he has to skip a gear or it will search and fail....making him have to pull over and shut down to get the tranny to go back to neutral. So once he's in 10th, he goes to 12, then 14 and so on...or it fails in the odd gears.
My mechanic never touched the transmission when he was working on the fuel pump...but he did pressure wash the side of the engine and that's where the engine ECM is located as well as the transmission ECU further back and down.
So I'm crawling under it in the morning to see if the washer knocked something loose or plug to a sensor got moisture in it.
Any other ideas from you folks?

 

Actually yeah I forgot to mention...the speedo is acting up. I haven't had a chance to drive it since my driver had it out. The output speed sensor was changed about a year ago. But I'm wondering if the water got into the plug somehow.
I'm going to pull that plug and ohm test it...along with the sensor. Maybe blow it out lightly with shop air

 

That's what I'm worried about. Gonna try drying things out and hopefully nothing got fried.

 

So I changed my output speed sensor tonight but still not working. Still getting codes relating to the output speed sensor.
It's weird because it'll go through the bottom gears fine...then when you go from 10th to 11th..it'll go into 11th and after a few seconds...the speedo drops to zero...it'll flash fail on the gear indicator...throw codes and then be stuck in that gear. Sometimes while it's doing this (as you're still driving)... if you put the controller to neutral...the speedo will suddenly come back on and it's in gear again. But not Everytime. Sometimes you have to stop and shut off the truck and wait for it to put itself back to neutral.
To me all signs point to the output speed sensor (which is now new) but it's odd that it only happens in high range and at the odd # gears.
My next guess is a break in the wire harness somewhere that goes to the speed sensor? Might take it The Gear Centre tomorrow about 2 hours away and let them try figure it out....because I'm kinda stumped.