4x4, transfer case problems HELP QUICK

I have a 1999 Chevy Silverado 1500 Z71 it has about 115,000 miles on
I have the switch board to select 4x4 hi and low
My service 4x4 light keeps coming on after i drive for about 10 minutes

But a couple weeks ago and this morning i got in and started to drive adn it felt weird so i looked it was in 4x4 low. Last time i was sure i didnt hit it. But i think i musta bumped it last night when i got home. but according to the manuel it will NOT engage in 4x4 low unless put in nuetral first. and it has once without going to nuetral and once completely by itself, im also getting a slight vibration and it feels like the hubs are locked when its in 2wd.


Anyone know whats up with it

THanks

I've heard about a lot of people having to replace the switches on thier auto xfer cases, its not too expensive of a fix.. sounds to me like this might be your problem, but, it is just a guess. I have the manual transfer case, and I'm glad!