I have a 1975 MB 240D, I was driving to work one day and I starting losing power, like I was running out of fuel, then it just died. I tried to start it and all I heard is "Clunk", so I replaced the starter and the solenoid and both battery cables to make sure I had a good connection, still nothing, I then replaced the ignition switch and have installed a brand new battery. I tried to turn the motor over and can't budge it, but when it stopped running, I didn't hear anything break. Any ideas?