I have a 1997 ford ranger, 4.0, 4 wheel drive.
I went to a mechanic and had some of the front end parts replaced. Upper/lower ball joints, upper lower tie rods, control arm, sway bar, bearings and 4x4 manual hubs replaced.

After it was all completed the mechanic told me I could drive it home but it would make some rattling noise because I would have to find a hub locking pin for the vehicle as he said it broke and once found he would install it for me no problem.
I called the ford dealership and they said they do not have it and cannot order it and auto parts stores told me they do not sell it either. How do I find this part; wrecking yard? If so what is the exact name of the part.

He said it was called a hub locking pin and that is the reason for the rattling.

I tried eBay- nothing, Google- nothing, dealership and auto parts stores nothing, and I cannot drive it until I get that part. Thank you in advance for helping me. The mechanic also stated I should not drive it at all or I could cause damage is that true?