Manual hubs locked on the highway, what might be broken?
 

A neighbor left the manual hubs on her Toyota locked and drove on the highway. When she got back to the apartment complex there was a little smoke coming from the back of her front wheels and you could smell the grease that was cooking.

My knowledge of 4 wheel drive is just about nil. What should I check on her rig and how should I check it? Bearings? Is there a way to check the hubs? The CV joints? I figured I'd check here since you guys have given me some good advice here before.

go to a toyota truck forum and ask. if it got hot enough to smell burning grease and see it smoking, you'll probably need new wheel bearings/hubs and lock assemblies. NOT something you want to be doing yourself if you don't know what you're doing.

Probably cooked the differential oil too - what happens is the tires are different diameters from normal 2 wheel drive wear and she was loading up the gears a lot extra when the wheels were sticking to dry pavement turning at different speed but coupled together by the 4 wheel drive (if she was in 4 wheel drive). On snow or slippery surfaces it is not a problem but on dry pavement it can be if there isn't a limited slip coupling between the front and rear wheel drive trains.
She should have noticed something was wrong but sometimes people just give it more gas and keep driving.

leaving 4wd on around town will smoke the tires before it smokes the diff. a front diff isn't any less ballsy than a rear diff. on the highway, the turning radius/distance thing won't matter and again, it'll do the tires in before the diff and won't bother the hubs. it takes a LOT to smoke a toyota diff. I had a friend drive a cressida...well lets just say stupidly fast very often and for at least 500 miles with no oil before it finally siezed up on the highway doing 90+ and ate itself. then drove another 15 miles after letting it cool down.

I'm now wodnering if there's a warning in the glove box manual saying don't drive over 55 with the hubs locked or something and she was doing 70+ on the hwy... overspeed/overheat the bearings and poof, she let out the magic smoke that makes things work. Either way, I'd bet it's an older truck and the hubs/bearings haven't been serviced/lubed in a while.