So we got a little snow around here and i had put my truck in 4WD and was going down a hill and the 4WD light went out and it was still engaged. I tried putting it in 2WD and it eventually came out. But what could cause it to kick in and out of 4WD?

 

ok, things to know about the 4WD system...
1. your light might be faulty
2. just cause you shift out of 4WD (or into it), doesn't mean it actually engages. Your speed, gear, load, acceleration ect will affect how fast it shifts into it.

while driving under 25mph, try putting it in neutral then shift into 4hi. Then put it back in drive. Does it stay in? Try the same when shifting out.
That helping the issue?

 

I usually try putting it in 4WD around 5mph or less. And sometimes i will put it in neutral and then reverse then drive to make sure it is locked in correctly. I don't like the idea of something trying to catch at 25+ mph

I will try what you said and see.

 

Sometimes the shift bars can get out of whack on the linkage. Not fully engaging all the way to the stops. I'd check there too.

Kurt

 

I say under 25mph cause I seem to remember something saying somewhere about not driving over 25mph with 4WD.

 

Id check your vacuum with a gauge and make sure theres no leaks. Maybe go under the truck and verify the lines are plugged in solidly on the transfer case and the axle CAD.
If its still not behaving properly you might want to pop the CAD and look to make sure the vacuum motor hasnt gone bad or the shaft got bent. It should go back and forth with no binding.