Transformers are almost never bad. Please be sure you are measuring correctly, you will need to switch both leads:
Also, to be clear, if you are not measuring AT the transformer, you don't KNOW what those voltages are. If you are measuring elsewhere in the circuit and just figuring it should be the same, you need to be darn sure about your assumptions and that no other switches are in the mix. From the sound of it, this may be the case.