Itowed a 19894x4blazer blazer behind my motor home with a towbarby putting the transfercase in neutural.Does anyone know how I can do the same with 1999 4x4 blazer?

 

Shouldn't have done it with the '89... Lubrication in the transfer case is not the same when it is in neutral. Its a good way to severely reduce the life of the input and rear output shaft bearings.

If you still want to tow it with the wheels on the ground, disconnect the rear driveshaft at the front of the rear differential, tape the u-joint cups in place, and strap it up to the underside of the body nice and tight so it A) doesn't fall out, and B) doesn't pull out of the transfercase at the front.