Yesterday I went around a small traffic circle to make a left turn and I heard a "clunk" sound in my transmission. I was only a half block from home, so I didn't notice anything else. Later, when I backed out of my driveway, the transmission sounded a little strange and I noticed the 4X4 light was on on my dashboard. I pushed the 4X4 High button on the dash to see if that would turn the light off, it didn't go off. I pushed the 4X4 Low button and the 4X4 Low light came on. Then I pushed the 4X4 Low button again, and the light went off and the transmission was back to its regular mode. I tried to see if it would happened again by "zipping" around the traffic circle again, but nothing happened. Everything seems to be running normally since then.
My question: Is this a rare quirk? Could it switch to 4X4 when I'm on the freeway? Can the Ford dealer run any tests to see if he/she can find something?
Thanks for any responses.
Tom