I need some help on where to start to look at my 4wd. Its a 97 1500. So I get stuck and the 4wd is working and then a pretty loud bang goes off and loose my front wheel drive. It is a console shift and it still turns the light on when it is engaged and it will still go into low range. Just nobody home up front. The cv's are still intact and so is the front drive shaft. Front diff or transfer case problem? any ideas? No grinding or clinking sounds after the bang just no 4wd.