Sadly, I can testify to the fact that W124 diffs can be a problem. Mine started to make a noise on the motorway halfway into a 250 mile journey. By the time I got home, it was pretty hard to ignore, and after a day or two it was into the local MB specialist I went.

The diff was shot to pieces, and I needed a new one. From Germany. £900 just for the part, before it was fitted. The car had just a shade under 80k on the clock. Not happy.

The (highly MB experienced) mechanic told me that although unusual, especially on that sort of mileage, it was not unheard of. The lowest mileage he'd replaced one on was 25k. That's gotta hurt.

It's still a great car, but that left a nasty taste in the mouth that's taking a while to get rid of. Am now petrified of any little rattle or squeak...