Hy 51ChevyDumper, welcome, you are correct with your theory on leak number one, it is most probably caused by a leaking rear main seal. Unfortunately "modern" two piece seals can't be used unless your engine has been changed to a newer engine, post 55 I believe, there are probably hundreds of posts here on rear main seal replacement, just use the search function and check some of them out. Your second leak is from your p.t.o. (power take off) shift shaft, clean the p.t.o. off and see if you can find a name on it, failing that, measure the shift shaft and the diameter of the hole the seal fits into, a good parts or bearing and seal shop should be able to find you a seal by dimensions. The leak from the dump cylinder could be more complicated, again clean and look for a name on the cylinder, failing that, you will have to dismantle the cylinder to find the dimensions and type of seal packing used in your cylinder. Be extremely careful with raising and blocking the dump bed to work on the hydraulic cylinder, good luck.
