1996 Chevy Suburban Low air flow in front, hot air only in

I changed blowers because of a bad bearing making noise. After installed the new blower (which I have bench tested for proper turning) I get very little air flow in the front outlets and good air flow but hot air only from the back outlets. Blower works at each selected speed and inside/outside selector works properly. The vacuum hose to the hot air valve located on the pass. Side under the hood was rotted and fell off so I replaced that. Valve works properly now. Any ideas as to why just changing the blower motor would cause such a problem, it's HOT out there here in Texas!