Front two wheels lock up. 91 Tercel

The wheels would lock up when the car was moving but the would free and roll again but now they are froze tight. I used a come along to drag the car on to a dolly, the wheels would roll slightly while pulling. I really don't think it can be the calipers, but it is a possibility. The trans axle, transmission what would cause this where do i fined info on how to fix the problem i bought a repair manual but it doesn't show how to work on the transmission just take it out and back in. please help