I assumed a "dimbulb" tester was just a light bulb wired in series instead of in parallel with the transformer.
Thanks for all the responses. Here is what Hammond provided for anyone searching this in the future
There is a difference between no load and full load. It’s called voltage regulation and it gives you the efficiency of the transformer. Kind of tells you how much loss you have in heat through the transformer. 132/120 = 10% loss or 90% efficient. As you load the transformer with current flowing the voltage will quickly toward the 120V. So don’t worry about the 132 volts with no current.
There is a difference between no load and full load. It’s called voltage regulation and it gives you the efficiency of the transformer. Kind of tells you how much loss you have in heat through the transformer. 132/120 = 10% loss or 90% efficient. As you load the transformer with current flowing the voltage will quickly toward the 120V. So don’t worry about the 132 volts with no current.