John Deere Woes... The A decides to die... (hopefully temporarily)

Yesterday after picking up all of the dead grass in our huge 3 acre mowed lawn I decided to take the tractor for a spin around some of the fields and out on the road to the back forty and back. It started out just fine, jumping to life and backing out of the barn just like normal. I then shifted into 4th gear and headed down the little country dirt road we live on. After about a quarter of a mile the engine went, "Pooomph! Paploomph! Chug.... Whine..." and then I turned it off. Only 3 families (all farms) live on my road so there I sat for about 10 minutes until some cousins came down the road in their truck. We towed it back to the farm and pushed it into the farm. There we tried to start it again... and to our dismay pure engine oil was taken all the way through the carborators and up through the filter and out the little overflow thing very near the top of the engine and just above the air filter. Oil sprayed everywere... We decided that something was VERY wrong. Then we took a petcock off and again to our dismay Antifreeze ran out! Arrrgh! With the suddenness of this all we think some valve inside the engine went kaplooey. A head gasket problem probably would have taken a bit more than a few seconds to develop...

Any other ideas?

By the way, everything in the clutch is lined up right, yet it still shakes! (Or did shake ;o( )

CE