Steering clutches frozen up

I haven't personally, but you should know that the clutches operate under spring pressure and when you press on the steering pedal you are compressing the springs and relaxing the clutch pack. That said, the “cerro-metallic” discs are not ceramic. They are not unlike those you would find in a marine or fork lift transmission which are intendedto run “wet”. But these don't because the brake bands won't like it. There are drain plugs in the bottom of the steering clutch housings that should be checked periodically for water contamination. If the dozer has sat idle for some period it's a good chance you are correct. If you can't free them up by judiciously applying a penetrating oil (avoid getting any oil on the brake bands), you will have to drop the swing frame and pull the final drive.

One thought; is the clutch release yoke secure on the shaft? In other words, does the yoke move in conjunction with the shaft?

sounds more like a linkage problem;  the disk in the clutch housing shouldn't seize unless the operator rode the pedal all the time or the linkage was way out of adjustment and overheated them;  but never heard of it happening;

remove the deck plate on that side and have someone in the seat to work the pedal so that you can get a good eyeball on the linkage,  one time i had a simular problem while working in small saplings and a piece of one had jamed the linkage and broke off,  but i could tell something was wrong cause the pedal was locked and would not move;

another possibility is that the roller pin that joins the pedal to the shaft has stripped and is allowing the pedal to operate with out engaging the linkage this would be more of a problem with the left clutch/brake that you describe;

keep us posted on the results

leon