What the heck was that!!!

[1963chevyc20]

It all started when I. Decided to go for my old 63 c20. I took a 20 mile trip to town. I picked up my newly purchased AR-15 and headed home. As I was pulling into the drive I decided to try something I.had bot done before and wanted to do. I would do a perlite in reverse! I revved the engine up, fixed that clutch let it out to take off and POP! Truck died. I started it back up and was just going to park it. I taped the gas and nothing happened. It didn't move! Oh. It was in neutral? Ok. Shifted to reverse to back it in to the barn and taped the gas while letting out the clutch. Vroooom! That's all that occurrd. At that time my sister ran out and said "something just Dell out from under you're truck!". Worried I jumped out to see a large puddle of oil and reverse laying in the dirt! Now my original 3 on the tree is no more! I am VERRY upset! It still runs and drives in 1st 2nd and3rd. Can I fix it?