A few months ago I was on a trail and came upon a hill with soft dirt and loose rocks beneath it. I started off good and slowed down due to another 4Runner a 5th gen trail edition kicking up a dust storm, my sr5 4Runner started to get stuck and my dash started beeping while the skid, Trac vsc lights started flashing. I was just wondering, is that normal?

 

I see this being an older thread but to answer the question for others using the search ability like they are supposed to.

That would be your traction control saying that your wheels are slipping and it is overriding your throttle and brakes to get traction back.

To avoid this as much as possible you can turn your traction control off before heading into loose gravel or sand and it will help. There is also an abs disable mod if you want to infringe into the electrical system a little bit that will allow you to turn the system off all together.

Quick other note for those traveling offroad at extreme angles, turn of the RSCA by pressing and holding the switch before traveling into extreme angles at speed. Even the transfer from the road to the gravel with a drop can make the system think your rolling the vehicle and possibly set this off.