We have two 627F scrapers and the one just started to not want to go into gear. It ran for a while with only 1st and 2nd and no reverse. If we put it in reverse it push forward when we gave it trottle like it was in 1st or second. We went to park it and reverse started working. Than we tried to go back to work and it wouldn't even go forward in 1st or 2nd. Seems to be electrical. Any ideas?