Stuck in 4 wheel drive low

Assuming yours is the 2 gear stick layout this is roughly how it works.
ONLY CHANGE BETWEEN 2 AND 4 WHEEL DRIVE WHEN STOPPED, IN NEUTRAL AND WITH THE PARKING BRAKE ON!!
The smaller gear shift should be to the left of the normal gearstick.
It should be in the fully forward position. This means it is in 2 wheel drive, high ratio, for normal road driving. (Rear wheels).
Pulling the stick back ONE notch engages 4 wheel drive, high ratio. Used for snowy, icy, slippery conditions as well as light off roading. (Keep the speed under 50mph).
Pushing down and back another notch engages neutral in the transfer box. This means ALL drive is DISCONNECTED even if you use the normal gearbox.
**Try to avoid this one**!!
Pulling the stick back the last notch engages 4 wheel drive, LOW ratio. This is for the more extreme off roading conditions such as VERY steep hills. Not usually used in normal day to day driving.
The two fully forward positions, (2High and 4High), will be the ones used the most.

no year?
never drive, part time 4wd on pavement, unless said pavement
is ice or snow covered.
only AWD allows pavement (tires direct upon) driviing.
part time 4wd is for offroad , off pavement driving,
this is because 4wd has no center differential.
http://en.wikipedia.org/wiki/Four-wheel_drive

and with out such, winds up the drive line fast. and breaks it.

wiki states (no year stated by you)
Part-time four-wheel drive was standard on all models. to 1991
then came
ActivTrak 4WD
cept
4H (high-range full time four-wheel drive), 4HLc (high-range four-wheel drive with locked center differential) and 4LLc (low-range four-wheel drive with locked center differential
so do not use LOCKED on pavement. on active track. only 4H
the wiki states the Super-select is retained 2006 to present.
Super-Select 4WD II

read the glove box manual under 4wd

wow, gee ... try shifting /disengaging in reverse?

to turn off your 4wheel drive you push the auto button. no light will come on and your vehicle will be ready to drive normal. only use low when stuck or steep incline..and high in snowy weather but never on dry roads

I assume that the vehicle has a rotating knob on the left side of the dash for four wheel drive. It may have been put into 4 low by mistake. To get it out, start the vehicle and put it in drive, select 4 low on the 4 wheel drive selector, take your foot off the brake and get the vehicle rolling at a walking pace (1-2 m.p.h.) then move the selector to 4 high, stop the vehicle and move selector to 2 high.

Be sure to put the truck in neutral, while engine is running, while you disengage from 4 wheel drive (low) to 4 wheel drive (high) and then finally to 2 wheel drive. It is critical to shift transmission into neutral when switching out of 4WD Low, as indicated in your owner's manual. Hopefully, this will help to FixYa problem!

Pull the kick panel on the passenger side. there is a small box mounted there that is the computer that controls the actuator for the 4wd system. this is notorious for problems due in fact that the connector likes to pull out and away from the module. I had the same problem and the solution is simple.. take a long zip tie and get it between a few of the wires and around the module. tie it in and have a nice day.. it wont come off or try to pop out anymore and you should have no issues getting into 2wd, 4wd h, 4wd L.

I ran across this problem with another vehicle....try putting it in another position (2 wheel high, 4 wheel high) and rocking it from drive to reverse, drive to reverse. Also try backing up at a pretty good clip and stepping on the brakes hard.....hope this works for you.

I have recently had this problem with a customer. It seems the 4x4 low will only engage in neutral with the brake applied. And also check fuse. Then select drive and you will feel it lock in. Don't "goose" the fuel when attempting this.

due to icy temperature the your brake fluid froze i suggest that you might flash the brake fluid..every 2 yrs the two thumbs up to flash your brake fluid because when it get old due the boiling point went low that can cause or losing brake in high or low temp..let me know what happen after flashing your old brake fluid