After driving it for about two hours on Saturday, I noticed a burning smell coming from underneath the car. No smoke, and it does NOT smell like burned oil or locked-up brakes but more like a mixture of burning wood, burning pizza, hot metal. Actually, much like a water kettle left on the stove too long.

Since it happened after I had driven through ominous black mud (which looked like it had a lot of decaying leaves in it) my first though was the exhaust system got coated with mud which is now burning off, but when I looked I couldn't see anything. No trash bag or debris either. At least that I can see.

Checked the transmission fluid which seems normal (reddish with normal oily smell).

No other symptoms, drove just fine, but whenever I got out of the car, especially with the engine running and the car in park, the smell was very noticable. Was unable to smell it after driving around town the next day.

Any suggestions welcome.