Just because you have a SkyGuard transceiver doesn't mean you're automatically going to see everything in the sky, now. But it should be lots better than it was before.
Make sure you've got the antennae plugged into the right connectors, and that the transmitter (blue blade antenna with the suction cup) is mounted vertically, and that both the transmit and receive anntennae have as clear a view as possible.
I fly a Cherokee, and have the transmit antenna in one of the center windows, which means the wing shades the broadcast. The box itself sits on the hat shelf in the back of the plane, which means the receive antenna is surrounded by the aluminum of the empennage. Still, I get solid weather performance, and pretty good (but not 100%) traffic.