Mondial T Valeo won't go into gear

I have one of the very few 1992 Mondial T Valeo cab. Love the car. Bought it a few years ago. Still need to go through the car and expecting RMT in Yorba Linda to do that in the coming weeks. Started it up to take it for a drive the other day and everything worked great. 1st gear pulled forward, reverse moved to another spot. Went to go back into 1st and take her for a spin and nothing. Won't go back into gear at all. The shifter moves between all gears. But, never goes into gear. I know that RMT can figure it out. Just seems like it wouldn't just go out from 1 second to the next. I'm definitely not a mechanic. But, any ideas out there?