My story would be like your but it's different.
I had my 84' Big Red for about a week (first ATC) and was just getting used to it.
We were out sledding at a gravel quarry when I experienced a few problems.
Problem 1: My brother says "You think the Big Red will climb that STEEP hill?"
Problem 2: I say : "Lets find out".
Everything goes good for a few moments - no problems. I shoot up the hill in 4th gear / low range and get midway, shift to 3rd, get about 3/4 the way up kick it down to 2nd..... Ok, here's where problem 3 starts.
Problem 3: 2 part problem
(1) I'm not leaning forward enough
(2) The rear tire is spinning in the snow and suddenly digs through to
the dirt. Tire goes from little traction to great traction in 1/1000 of a
second. It appened so fast but I can tell you what DIDNT happen.
The bike didnt shoot up the hill
That Red came over so fast I dont even think it registered for a couple seconds, one second I was riding the bike up the hill and the next it was riding me down the hill. The trike flipped over and I'm laying on my back, feet still on the pegs, hands still on the bars, slidding down the snowy hill on my back
Had to just lay it over to the left to get it off me / broke the left brake lever and learned to lean forward more when climbing.
Here's a pic of my 84' and one of it stuck(I thought they didnt get stuck

)