Yes—this is generally normal. A more advanced DSLR is not necessarily quieter, and in some cases it can be louder.

With the 7D, the mirror and shutter mechanism may be larger and move faster than on the XTi, which can increase shutter noise. The 7D also has a faster maximum shutter speed, and higher-performance internals often prioritize speed and responsiveness over quiet operation.

For the lens, both are USM designs, which are usually fairly quiet, but the 28-135mm IS lens can add some extra sound from the image stabilizer, and faster autofocus action can also be more noticeable.

The 7D does offer quieter shooting options, but they are limited: its silent shooting modes work in Live View rather than standard viewfinder shooting. Those modes reduce noise by changing how the shutter/mirror operation is handled, though there may be tradeoffs in speed or autofocus behavior.

So if the camera and lens are functioning normally otherwise, the extra noise is most likely just a characteristic of the 7D and lens combination, not a fault.