The truss started out as 2x4 3/16 tube. I more or less cut it in half on the two inch side to keep it low to the pumpkin because as you said, space is a premium. I actually left about 3/4" of steel on that short side. I thought the short side walls would resist the twisting, but apparently there was not enough to resist the forces.
So yeah, it twisted. I have some ideas on adding some 1/4 plate to the back of the existing truss. It should box in the existing steel. And then weld the added plate to the pumpkin. I will get a shot of what I am talking about later.
I fired up my trusty OLD (really old) SMAW tonight and repaired the cracks. I am not a great welder and even worse with the stick. I laid down a lot of material over the cracked weld and got a bead over the crack near the UCA mount. I also added some material to the existing welds on the UCA mount for good measure.
Winter is starting to set in here in the Rockies. I hope the repair can get me through till the trails are blocked. Then I can focus on the front truss.