Pertaining to the OP's vehicle, it may be possible for him to take his truck to a parts store like Vatozone, Advance, Murrays, or any of the like, to have one of their workers attach a code reader to his ALDL and retrieve the stored ABS codes, if any are stored.
If no codes are stored, IMHO, unless one has a scanner that does live data, he'd be SOL.
If there is a scanner present that shows live data, all that would be needed was to duplicate the complaint, and look over the data to see which ABS sensor is not reading right, then begin diagnosis.
It has been my own perception, but I have noticed that the most common culprit to be the r/f ABS sensor. And the EBCM (Electronic Brake Control Module).