can anyone tell me if i can put a 99-06 half ton rear end under my 96 tahoe? any mesurments will be helpful  

Same rear and width for both trucks, so that's not a problem. The only issue is if both have leaf springs. I know the trucks do, but I can't remember if the Tahoes do or not.

I think the Tahoes have leaf springs like the trucks though, so it should be a straight swap.

One issue though, unless your '96 is 4WD, the '99-'06 trucks have six lug axles, while the 2WD '96 has five lug axles.