Hi ATL4R,
I've worked for many years (upwards of thirty five), as a mechanic. And I get it, "safety first". The things you mentioned, are extra precautions, nothing wrong with that; I''ll often take some extra safety steps too if I feel I need to (tis' a judgement call).
Additionally, I could have advised by the book, telling the operator to "Remove both drive shafts before starting...", but I opted not to because my focus was mainly to help him locate the source of his rattle, not to instruct him in the importance of observing safety standards.
If I thought that the OP was incompetent, I might have advised him to take the truck back to the dealership, because the scope of the job is beyond that which could be safely done in the driveway.
With all of these extra safety measures that I opted not to discuss, being very careful was implied when I instructed to "chock the wheels" along with setting the parking brake. The advise that I offered still was not bad advise; not by far. Thanks again for your input.
rigtec, cheers