I have a 2011 chevy duramax four wheel drive. I had it in 4 high at my deer lease and when i pulled out on the road i forgot to change to 2 high. It started shaking i pulled over and front end locked.

Inspect the front differential fluid for metal and look at the transfer case fluid also.

I smelt a gear oil when i got pulled over.

Not a good sign.

Im thinking maybe ringear and pinion shattered should see it when i drop gear oil.

It was shaking front end like a tire out of ballance.

Probably if you are smelling oil after the lockup something let go in the front differential and it could very well be a ring and pinion or perhaps the pinion bearing went, carrier cap broke or something like that. Post back and let us know what you found.