Tell if 4x4 is engaged from outside?

I was driving my 4x4 OR to Tahoe this weekend. Chain controls were in effect, but I was driving in 2wd. I got stopped at the chain control checkpoint and the guy looked at my front tires and told me to shift into 4wd. I never spun the tires in the checkpoint line or did anything to alert him to the fact that I was not in 4wd. How was he able to tell that I was in 2wd?

 

Probably just a lucky guess. He probably just says that to everyone that has their window down. Plus if you put your window down and talked to the guy he was probably just double checking. Whenever I go though chain controls i don't bother putting my window down and just waive and he flags me though. I go though I80 and 50 chain controls at least 3 -4 times a month and i have yet to ever put my window down.

 

Is he able to see the half shaft? If it was not spinning that is pretty obvious.

 

When there's a few hundred cars/ semis backed up they can't look at everyone's undercarriage. They just have to take the drivers word for it. Plus if you blow though the check without chains or a 4wd you'll get a reckless driving ticket when you spin out.

 

I waived at him with the window up thinking he would for sure wave me through, but he looked and then motioned for me to stop. I'm lifted, but I don't think he could see the half shaft from his angle. He actually told me to lock my hubs. I left the checkpoint in 4wd, but was confused over how he knew I didn't have it engaged.

 

I carry chains to avoid a potential ticket, but if the conditions are so bad as to necessitate chains on a 4x4, I'll probably just stay home.

 

On the 2gen, the half shafts are always spinning when the truck is moving. On 1st gens, the half shafts spin all the time unless you have the manual hub option.