Might find some info here...

http://www.ssbtractor.com/wwwboard/messages6/

SolarEagle: Has the best response, an actual John Deere blog site.

It would be a good idea to pick up a service/repair manual, they do come in handy.

Off the top,

- check your oil supply

- supply pump going gone

- I take it that the cylinder is a double acting ram. could be packing is gone.

but these are only a guess

I too have a JD tractor. I have had hoses rupture from overloading the bucket, but never a steering freeze.

Have you checked to see if a loss of hydraulic oil has occurred?

Can you move the steering cylinder with the wheels off the ground by moving the front wheels (engine off)?

Do the bucket hydraulics and 3 point still work?

It's also possible you have some air in a hydraulic line.

Thanks guys. I pulled the cylinder and the piston came unscrewed from the shaft. The cylinder seems to be unserviceable. Any ideas on removing the head to access the piston or is it toast.

Gland nut should come off to repair it. Anyway to post a picture of the cylinder. There are a few different ways in which it's retained.

take the cyl. to a local hydraulics shop. If it can be repaired they will be able to quote a price. If it is BER(beyond economical repair) they should be able to get you a new generic one at a far better price than OEM.