4WD Noise

I have a 2002 Blazer that makes a loud bang and shakes the whole truck when going out of 4WD into 2WD. Does any one know what the problem is?

Thanks

Specifically 4 Hi or 4 Lo cause if 4 Lo probably the transfer case engagement motor and if only 4 Hi probably the front pass side axle coupler. Get a helper to do it while you pinpoint the origin - also gear lash in the whole drive train so you have to get where its coming from for a fix.

Had the same problem with the wifes '98. Spent (wasted) a lot of time looking for the cause. Thanks to this forum, I found the SIMPLE answer.

The front and rear tires HAVE to be the same size. If you have not been rotating your tires and the fronts have worn more than the back, this "noise" will show up. When you think about it, it will be clear.

T