Mohgasm 1.8a driver current test. Is this normal?

I am testing a Mohgasm driver I have. Its 1.8 constant current and I'm powering it with 2 3.7v 4000mah 18650's. I hook up the meter to the LD- and LD+ on the driver and it says 1.73a. This is good.

My problem is that although I have a heatsink on top of the regulator on the driver, it still gets very hot very fast. Too hot to touch if I let it test for 10 seconds. Is this normal?

Thanks in advance to all the great help here! I appreciate every piece of input!

What's your driving load? I.e. what's the Vf of the diode you are using (or test load)? If it's too low, then the driver will drop the rest of the voltage as heat (that's what linear drivers do).

I'm sorry I don't understand what you are asking me. I desoldered the diode from the driver and I am just testing the driver with a multimeter. As soon as I connect the multimeter to the driver it begins to get really hot fast. The multimeter is showing the current at 1.74A and 7.5 volts. This does not seem right. Aren't these drivers supposed to only put out around 5 volts?

You should NEVER test a driver without a test load. These drivers do not regulate voltage, they regulate current. Do some research before you burn that thing out!