Check 4wd light, 1999 GMC
I have a '99 GMC 3/4 ton 4x4. I while back the check 4wd light came on the information center. I checked minor things to make sure it wasn't something obvious, like low oil. Nothing obvious wrong. It is the push button 4x4.
I have used the 4wd twice, and I've owned it since new, so I really can't see it as the transfer case piled-up. I use it just to pull my race car around so it has pretty low miles around 90k. All on clean highways, and its never been offroad.
When I try to get it into 4wd the light blinks for a while, and sometimes it engages, and sometimes it doesn't. Also some of the time it takes quite a while to come out of 4 wheel, back to 2 wheel.
I have tried it in 4wd and driving the truck around, and it makes a terrible noise, and slows the truck quite a bit. I have also dropped the front drive shaft for a week and drove the truck while I replaced u-joints. The same noise happened when I tried it in 4 wheel drive if it helps.
My question is: if the actuators or something else are not fully engaging the 4wd, would the truck make all this noise? What could be the problem here?
I'm definately no mechanic, but I do all my own work on my vehicles and race cars. If anybody has any idea what this could be let me know.
Finally I hate these new computer controlled trucks, when this is finally dealt with it will back to the early 80's trucks for me.