You may already know this as a truck technician but here is what I have to offer.
Traction control is usually activated while driving when the wheel speed sensors detect a variance in speed between all of the wheels, and will attempt to compensate to bring them back to equal speeds. There are usually three possibilities. The speed sensor in the wheel hub is failing and sending the wrong signals, the wire connector for the speed sensor is dirty/corroded/wet, or the wiring itself has bends/breaks/cuts usually from the wheel turning or the wire rubbing over time.
I would get a good computer code reader on there if you can to see if there are any stored codes to point you to a specific wheel that could be at fault. Has your ABS light ever come on unexpectedly? ABS is activated based on the readings of the same speed sensors but during braking. If the ABS light comes on, there may be a trouble code stored in the computer that points to a specific wheel.
If you cant find a code reader or there are no codes, I would start by checking the wiring for each wheel speed sensor to the best of your ability for breaks/cuts/splits/rubbing. Then carefully disconnect each speed sensor wire connector and clean them out if needed to make sure they are getting good contact.
Please keep me posted on your fix. I would like to know what is actually at fault.