i have a 84 300 sd i traded for from a friend of mine that was wrecked but ran.ive fixed the wreck damage replaced hood etc . ive cleaned banjo fittings changed all the filters and hoses new radiator new thermostat . ive checked the shut off valve with a vacuuum tester shut right off and holds pressure.i had a bunch of vacuum leaks . ive replaced alot of the fittings and got alot of it fixed but the car wont shut off from the key switch and while the engine seems to be strong the car wont shift and go above 30 at 30 35 mph its at 3000 rpm . i changed trans fluid put a new filter in it no metal shavings in pan .replaced the rubber nipple on the hardline where it connects to the side of the transmission checked vacuum there got alot you can feel it suck on your finger but very little vacuum at the keyswitch it will shut off if i drive it but only after a few minutes