Bang, thunk, thunk, thunk

[Isaac1]

Driving home at sunset I had something strange happen to my 2007 Yaris with Manual Transmission at 218,000 miles. 5 miles from home I merged onto a highway and noticed a strange buzzing sound as I shifted into 4th and 5th, the temperature here was right at freezing, after a cold front came through earlier in the day.

Then about half a mile from home I was driving along going straight in a 35 mph zone when something suddenly went BANG, clunk clunk clunk, imagine what it would sound like if you were to drop a brick into a washing machine on spin cycle, and you will have a good idea of what it sounded like.

I instantly hit the clutch and dropped it into neutral, and the sound went away, I gently revved the engine in neutral and everything sounded ok. I gently put it back into 3rd gear let off on the clutch and I was able to make it the remaining 1/2 mile to my house, though I did not give it anymore gas than necessary. I had to stop due to oncoming traffic before making a left turn into my driveway, downshifting into first, I was able to pull into the driveway, and stop the car, all of this sounded normal.

Now for the big question, any thoughts on what I should inspect when I have daylight in the morning, I KNOW I did not hit anything, but have no idea what might go bang, thunk, thunk, thunk then have the engine and transmission seemingly drive ok afterward (note I have not tried 4th or 5th gear since the sound)

thanks