I Accidentally pressed the differential lock button at high speed. Did I damage the vehicle?

I have a 96 Toyota RAV4. I was driving about 75-80 mph, and accidentally pressed the differential lock button which set of some kind of beeping sound (the button is directly below the AC.). I tried pressing the button again, but the sound continued. I pulled over, stopped, and pressed the button again. The sound stopped, and everything seemed OK. The vehicle "felt" normal when driving, and there were no unusual sounds. A few miles later, I pulled into the garage and noticed a faint smell somewhat like burnt motor oil. The vehicle has a slow oil leak, but due to what happened, I'm a bit paranoid that I may have damaged something.