I played through Downhill recently on hardcore, I had two 375s (that spawned in game, I changed equipment on them though) loaded in the SW log kiosk. One was equipped with a crane to load both. As I left the one with crane parked close to the kiosk, I loaded both trucks with no problem. I pulled the loaded craneless truck across the river with a 535 and left it parked on the road to the right, pointed towards the watchpoint, just before the road that goes uphill to the left, beside a couple trees but not touching them.
It was then that a seen a message about a truck taking a ton of damage. It was the truck I left parked beside the kiosk. It took a random 500+ damage that kept the engine in it from running. I had to bring a 255 from way up north all the way down with a utility trailer to fix it. I drove the 535 back across the river to the kiosk and winched the newly repaired 375 to the back of the it. I was about to cross the river when another damage to a truck occurred, this one on the 375 I left parked near the road!
The truck had been randomly thrown on it's side and lost the load! It only took about 300 damage though. I used the repair kit the 535 had on it after I pulled it back upright. I reloaded the logs and decided to keep trucks separate until I could top the hill to the south. I got both 375s to the top of the hill individually and then winched back together to go all the way back to the lumber mill in the SE.
These random damage events almost ruined that game for me. It caused me to take even more time on this map which I used to achieve the Blind Navigation achievement.