I just bought an 99 ranger sport 4x4 with a 3.0. When i engage 4hi the light comes on and I hear a noise but nothing happens when I engage 4lo nothing at all happens no light or no noise. I'm just looking for something to try before bringing it to a mechanic.Thanks

 

are you at 0mph, putting it in neutral with your foot on the brake before engaging 4 low? if not, theres why its not going into 4 low.

for it "not working" your PVH hubs may be toast, its common for them to stop working.