depending on how high you lifted the back end, it is possible that you made some fluid come out of the vent on the top of the trans. Clean up the area and watch it for a few days. If you want to verify it is trans fluid, touch it and smell it, gear oil is rather smelly. Swepco is blue, but you might have other trans fluid as well.
For the 83, you should be able to replace the seal from outside of the trans, but you have to split it from the engine to get to the input shaft. You'll need to drop the engine. I think our host here sells everything you need.
