I have a 76 300d with a transmission problem. The readiator had just been cored and cleaned. On the way home, the cooling line that goes from the tranny to the radiator exploded and leaked all the fluid out. I drove the car for about a mile down the road (oblivious to the carnage underneath) until the tranny began to slip.
I had the line fixed to see if the transmission was toast. It slips whenever I try to accelerate. If I drop it down to second it doesnt slip at all. I have heard that there is some ajustment with the bands, but automatic transmissions are rather mysterious to me. I don't know if its time to drop this tranny or try to fix it.