4wd engagement and the front shaft of a toyota 4runner 1999 model

i own a 1999 model toyota 4runner and have over 250k on it. my terrain is rough and i usually engage the 4wd frequently (4h often). recently i noticed that while trying to make a turn, the vehicle would not move forward. rather i heard a crackling sound from beneath the vehicle. i immediately disengaged the 4wd mode from 4h to 2h and the vehicle moved.now i am bothered because i keep hearing a harsh ticking sound from the left front wheel and i am thinking the shaft is bad. also, the 4wd indicator on the console keeps blinking even without engaging it. pls what is the relationship between the shaft and the 4wd system? is my 4wd system damaged? does the fault involve both shaft and 4wd system? kindly advice me pls.

Where you on a dry surface while in 4H? If so this can cause the transfer case to bind up.

A 4WD system doesn’t have center differential like an AWD system does. Because of this, a 4WD system can’t allow the front and rear differentials to rotate at different rates. This becomes a bigger problem when the front wheels are turned as you found out.

The crackling sound you heard was probably the transfer case binding up as you tried to move forward with the front wheels turned. And who knows what that did to the transfer case.

Tester

Could be a bad cv joint or a problem with the actuator on the front differential that engages it or the transfer case pit self. If it does not fully engage, it will blink. You need to take it to a shop with 4wd truck based systems experience and have it evaluated.
Are you the original owner ? . If you put all 250 k on this vehicle we assume you know how not to drive it on dry pavement when engaged. If no, like @tester indicated, you might have done some damage to an older system that with fewer miles, could have taken a little abuse which off roading.

@tester.tenx for the input. yes i was on a dry surface when it occurred.if it is the transfer case that is damaged, please what does this portend with respect to repair cost and utility derivable after repair.
@dagosa.tenx. i am not the original owner.picked up the car about 8weeks ago with 267k on it.its my first truck.read up something in its manual that says the 4wd must be driven for at least 16km per month to preserve its overall functionality.i will take it to a shop like you adviced for proper evaluation.i just hope the repair cost wouldnt sink boulder sized holes in my pocket.

@chyneme‌
Let us know how it turns out. Yes, you should run it monthly. But, you need not run the the recommended distance concurrently. In the past, I would either find a dirt road that was in my travels or only drive the straightest route and never take corners. When I came to a corner, slow down and take it out of 4 wd. Overall, it is a very old vehicle mileage wise to buy with 4wd and not expect problems. It’s the nature of the beast. The system will last the life of the car if treated well…but this probably hasn’t been.