Code comes up as po743 truck running great

P0743 is a transmission fault code related to torque converter clutch (TCC) solenoid performance.
The tests necessary to isolate the solenoid are extensive. A knowledgeable trans tech may say replace the solenoid, but the fault could be only the harness. All of this is internal to the transmission.

Po743 is gone transsmission was 2 quarts low on fluid now have code po443 and po753 can you tell me what they are

Truck runnes fine but have 2 codes coming up now po443 andpo753 can someone tell me what they are and how to fix them please

PO753 is Shift Solenoid "A" Electrical

Is that inside the transmission

is that inside the transmission

Yes, that solenoid is in the transmission, mounted to the valve body.
That code may have been set due to low fluid.
The other code, P0443, is for the Evap Purge Solenoid. It is unrelated to your transmission issues.

If you haven't done so already, fill the transmission as necessary.
Make certain the fuel fill cap is proplerly installed and the seal is not worn or torn from repeated use.
Then have the codes cleared with an appropriate scan tool and then drive the truck to see if either code comes back. If they do, they are considered HARD codes and will need further hands-on diagnosis.