The transformer is cool to the touch.
Now, the only other thing I can think of is as others have noted there may be others near you whose WiFi routers will interfere with yours if both are trying to use that same channel at the same time. Many other things can also interfere, like microwaves, cell phones, radio transmitters CB,Ham etc, television stations and radars.
If you have an Android smartphone or tablet, with WiFi, you can use the device’s WiFi setup to seek out any other WiFi routers in your nearby situation and see if they may be overpowering yours.....................