Progress report, of a sort. I went up to Manchester today, dropped off my 500E, and drove the 280SL home. Overall, the engine seems to like these ratios. Shifting is still rather tight and requires more effort than I would expect from a used gearbox which presumably was already broken in. There is a bit more noise from the Getrag than the original gearbox made, but not excessive. We have two rattles: the first, a low-pitched bang on bumps, seems to be from the exhaust system hitting a bolt which I think is part of the transmission mount. We will probably have to either put high-temp padding between them, or dimple the exhaust system in that area to give it more room.
The second, which is far more annoying, is a higher-pitched rattling which seems to come from the area of the glovebox. It is most noticeable at highway speed in either 4th or 5th. Not sure what that is. I really hope it isn't the speedo cable- getting the cable in the first place was a huge pain, If I had to replace it I would not be happy.
I'm going to drive the car for a few more days and see what else turns up. Overall, it isn't perfect, but it's better than what came out of the car, and I hope that we can sort out the rattles and complete things.
At 3000 revs the speedo indicated 60mph, which is handy since I'm terrible at math, but I suspect she's going faster. I'm going to check it tomorrow with a GPS navigator and see how close we are. We just connected the speedo to the trans with a cable and no adapter, so it would be too much to hope for that it would be accurate. Plan is to get an idea of the error and this winter send the unit to Palo Alto and get it recalibrated.
Stay tuned!!! GGR, if you want to come out here and drive the car, I'd be delighted to show it to you!! the impression of an expert would be most welcome.