On the PFD in a 737?
Besides, it really depends what kind of box you have fitted and what the company advised SOPs for that box are. For ours (yes 737s as well) it is to let the transponder in TA/RA all the time except during degraded performance where we switch to TA. TCAS as such shouldn't have any problem with that as was described above very aptly by Graybeard.