My truck quit on me. It was leaking transmission fluid all over the place and wouldn't run. A guy who helped me push it to the side of the road (said he was a trans. guy for 20 years...) said it was my main seal. Broken. What does this mean? Would I have to replace the whole transmission? How much is a reasonable price for the whole thing? What about just the seal? Are there any important questions I should ask of the mechanics? How long does this usually take?

Thanks in advance.

JRDean