Ok, so I have a 01 silverado, a couple of weeks ago I'm leaving work heading for home, just as soon as I hit the highway, I hear a god awful grinding noise, and I'm pressing the gas and not moving. So long story short I somehow got it off the road and had it towed it home. At home as soon as I put it in gear the grinding noise returns, so I crawl under it and have the old lady put it in drive, to me it sounds like it's coming from the transfer case. So I pull the thing out take it all apart down to little pieces, and cannot find anything wrong with it, no spun bearings, no stripped gears, input shaft splines look great on both ends... Put it all back in and viola it works fine! So I go to take it for a test drive down the street and as soon as I stop and go to take off again, the grinding noise returns, I'm not moving anymore and I have to walk back up the street and drag the damn thing home again!! What the heck can the problem be?? The part that really gets me is that when it breaks it doesn't matter what range the transfer case is in, I'm not going anywhere. I'm almost certain it's not the transmission because when it does work without the grinding noise I have tons of power, and I've ruined my fair share of automatic transmissions and have never ever heard grinding come from them! But it seems like when it starts grinding if I cycle through the ranges on the transfer case it will fix itself. From the times I've done it, all I did was shift the transfer case into neutral and then back into 2wd. The only thing I can even remotely come up with is that maybe the motor for shifting through the ranges isn't quite shifting completely in between each range, and the transfer case is getting hung up between two ranges. Or maybe the torque converter is broken somehow and it catches sometimes and works fine and other times it's just spinning. I'm totally lost on what the problem could be, and I can't really afford to take it in to have someone else tell me what's wrong with it. Anyone have any ideas or suggestions???? PLEASE HELP!!