I was recently cruising up a long hill in too high a gear, although there were no issues it put the SES light on - It's hapened before several times so I'm not bothered about that.

However, being that it was dark and the SES light was blinding me and there wasn't anywhere suitable to pull in and switch off to cancel it, I decided to do a rolling switch-off.

I slowed to about 20 put the clutch in (I think this was a mistake) switched the ignition off and on again then let the clutch up to bump the engine back into life (I should have left the clutch alone). Anyway the driveline took quite a shock from this and ever since I have an intermittent knock coming from underneath at the back somewhere. It does it every now and then while cruising along a flat, but also seems driving the passenger side tire over a pothole makes it thump too.

What did I break? What do I need to check?

And after all this, the rolling switch off didn't even reset the SES light!