On my 71 F100 I found out that the transmission shop cut the rivets out of a cross member and bolted it back in after the job was done. That wasn't the only "shortcut" they took, and needless to say, I haven't taken them any work since then. I was so torqued over the job they did, I paid them in $1 bills, all 832 of them. They were lucky I didn't have that many pennies.