When turning sharp turns left or right sounds like front end is coming out of it

Your description sounds like it is stuck in 4WD or at the least shifting into 4WD when not needed. That would make it bunny hop and noisy, it also means it is likely doing damage if you are driving on high traction surfaces like bare pavement or similar surfaces that do not allow wheel slip.
There are a couple of common causes for this problem. The most common is the actuator motor the next is a failed speed sensor. Being you have a flashing light you have a code or codes stored. You should start by getting the truck scanned with a dealer level scan tool that can read the transfer case codes. That will give you a starting point at least.

Getting it fixed should be a priority as it can easily damage the transfer case or front axle and may have already, hard to say for sure.
Because of the way that case operates you may be able to pull the front drive shaft and still be able to drive it. Be sure to make marks on both of the joints on the shaft before you remove it. That way you don't disturb the balance of the unit.

While it isn't a difficult thing I would suggest you have a shop look at it to verify what the problem is. They may be able to test it as well. If it is something like a faulty speed sensor it would be better to repair it now rather than wait. Plus they could give you a better idea of any damage because they can see and hear the issue in person.
To remove the shaft isn't hard, it is a bolt in part. You remove the bolts shown in the pictures, then remove the shaft. The hardest part is usually getting the vehicle in a position to remove them.
Another option might be to simply disable the transfer case motor and clutch coil. That would involve making sure it is in 2WD and then unplugging the connection under the truck.

Or possibly even easier, would be to remove the fuse that powers that system. That would be fuse 6, a 20 amp maxi fuse in the power distribution box. It powers the transfer case relay and should shut the system off.

For all of the above you need to be sure that the case is in 2 wheel drive before trying it, if it is in 4WD it can still do damage even with the parts or fuse out.