Hello everyone, first post, great site. So much info here. Sorry for not doing a formal intro but my trucks 4 wheel drive has not been working and it's driving me crazy. 2002 F150 xl, manual tranny. 4 wheel shift on the floor. When I switch from 2H to 4H the 4+4 dash light comes on but the 4 wheel doesn't engage. When I switch back to 2H the light goes out. I can also here it click in the dash and the 4 low light works as well. But after driving for about 30 min the truck acts differently. When I switch the floor shift to 4H the light again comes on but stays on when switching back to 2H. So now the 4by4 dash light is stuck on. I still don't have 4 wheel, and it will now grind when switching on the fly. Before the 4 wheel light was stuck on, switching on the fly did not cause any grinding. If I let the truck sit awhile, the 4 wheel light will again function properly, only to malfunction shortly thereafter. Any ideas of what's going on? I'm thinking maybe a solenoid because it seems to be delayed after i start it up. Maybe when the truck gets to operating temp? Any suggestions is appreciated and will be passed on to my mechanic who hopefully knows how to properly diagnose this correctly. Just to recap, I have two problems. The first is the 4 wheel not engaging despite the dash light indicating it is engaged. The second problem 30 minutes after. The 4 wheel drive light stays on and grinding occurs when shifting on the fly. In both situations the 4 wheel never engages. Thanks in advance.