2007 Kenworth T2000 fault codes?

The truck in question is a 2007 Kenworth T2000 with Cat and a 10sp Automatic transmission, last eight if the vin: 7J155556.

I just had a driver call and the truck was running down the highway just fine and all of the sudden came out of gear and went into Neutral even even though the dash read 10 (10th gear). He had a code of Sid 031 on the dash. He coasted to a stop and it seem to be stuck in Neutral and would do anything? He shut the truck off, cycled the key a few times, then started it. It was back in neutral, he put it in D and headed down the road and everything is shifting fine and driving fine right now.
After about 10 minutes of driving he got a message on his dash of "Rd Spd Short Circuit". I have never heard of this. He said everything is driving fine currently.

Can someone help out this these 2 messages?

Thanks.