1985 Toyota Tacoma Engine

My buddy and I took his older Tacoma out to the sand hills and were doing fine. His truck has a standard transmition and we had it in first gear on 4h haulin butt up the hill. After the second time going up, (i was driving), I pressed the clutch and brake to bring the truck to a normal stop at the top of the hill. After I did this, the rpms on the truck maxed out at 8000 so my buddy reached over and cut the truck off, and we were hearing a thud under the hood. We popped the hood and the belt was popped of and the truck was leaking a bunch of oil. I went ahead and did what I could to the best of my knowledge and pit the belt back on and looked for the source of the leak but no luck. We eventually gave up. Locked the truck and left it in the desert and headed back to my truck. How can we get the truck off the hill? The brakes are locked up and if we start it to unlock them and put it in neutral, we get that terrible thud under the hood. Please help