Toro 26622 won't move on it's own.

I have a 1990 26622 Toro. Just given to me in return for a clean up job at a friend's house. It runs and mows fine. The Blade Brake Clutch works fine. It won't move by itself. The speed control lever is very hard to move, in any direction. I want to get a look at it where it attaches to the trans. Can anyone tell me how to access the trans end of the cable? Thanks.