If all 4 wheels are on floor then it won't push anywhere, its locked solid. If rear wheels only are on floor then front wheels turn the opposite way and vice versa. Also with any three wheels on the floor the other one goes backwards. Both shafts seem to turn OK.
Everything is working OK, its just the front wheels seem to be turning the opposite way to the rear wheels. Nothing has been changed since I used it last time when it worked OK.