'87 300D transmission died
 

Over the weekend I was driving a lot and noticed the transmission wasn't quite happy, it would shift unusually and not go into gear as quickly. On monday I checked the transmission fluid and it was really low! I immediately added more and it got a little better, still not much problem. But tuesda,y morning when I put the car into drive, the motor spun up and the car sat there like it was in neutral. I was able to drive it a little after it warmed up, but it was all pissed off, worked best in reverse. Wednesday I ordered a new transmission ($550 delivered) and found someone to switch it for 350. I noticed transmission fluid was leaking from where the transmission cooler line goes into the transmission, I guess low fluid was the cause of failure. How messed up is the old transmission which got run with low fluid? Should I recycle it for scrap or get it to someone who rebuilds them? Thursday he switched it and filled it with Dextron III / MERC transmission fluid and it worked great for a bit, and he left. Later after driving it one mile more, it started making a loud whining noise. Seems like its coming from the transmission. So at the moment the car works great except that it is extra loud, the whine is about half as loud as the engine, and changes pitch as I step on the gas. Seems like the sound is coming from the transmission, maybe the front of it. What can I do to get this new transmission working properly?

perhaps the installer guy left disconnected the exhaust to make some wiggle room for the trans job?

$550 for a transmission delivered, you might have gotten what you paid for. Do you know anything about the history of the transmission? It sounds like the front pump (hydraulic pump whine), might be fine, be sure the fluid isn't overfilled.