These were plagued with a weak transmission cooler ( now quite popular in current vehicles) located at the lower tank in the radiator. IF, perchance, that is the the original rad, then the engine may have inadvertently mixed the coolant and transmission fluid. That would be bad. Usually though there would be at least some warning, no power going uphill, weak acceleration, lots of flaring....and if you pull the radiator cap you'll see oil floating around. If you have no oil in the rad you _should_ be alright on that front. Complete loss of drive and reverse does sound like more of a relay / elecritical power issue rather than a solenoid. Never heard of multiple solenoids all dying at the exact same time. I would look at the electrical side of things first, mostly a loose or broken ground cable is what I am suspecting, but don't rule out anything yet!