3 weekends ago i was going around a wide curve when my tire fell off the side of the road and sent me sliding off the other side of the road into a field.it had been raining for the past 2 or 3 days and of course landed right in the middle of mud hole. i kick in the four wheel drive and tried to spin myself out unsuccesssfuly.pulled it out of the field and drove it about 10 miles home. once when i stopped an intersection something clunked and the truck jerked when i went to take off.changed my clothes and went to leave to go to church. i had to back up and then pull back up into driveway so i could get out. when i put it into reverse so i could back out the truck clunked and jerked again.since then reverse gear has not worked and overdrive is picky about working, when i drove it up to the shop to work on it the tran wouldn't shift to to 3rd gear(sounded like a manaul when you have in too low a gear).took off the pan and found that about an inch long chunk had blown out of the valve body gasket beside the reverse servo. replaced that and put back together and still no reverse. a friend of my grandfather who's a mechanic said to change around the reverse engagement valve because before all this started tran was sluggish about shifting into reverse and was proven to help.we did that and put it back together and still had no reverse. finally took tran completely apart to check the sprag and found that it was slipping. put in newe race bearing,sprag clutches and check evey other part. put back together and still no reverse but rest of the gears just as good if not better than they origanally did. i am dont know much about vechiles once you get basic service and only thing my father and grand father can think of is that didnt put the reverse engagement valve back together like we were supposed to or we need to completely redo the valve body because it is a C4 and we figure stir up some of the slush in the bottom and it has caused something to get stuck.

i would really appreciate any other ideas anybody can think.