That's always been my preferred method too. I still have pickle-forks in my collection, but ever since the first time I used one on a part I intended to reuse, I just couldn't bring myself to do it again. Even if the part was going to be replaced anyway, I still got out the hammers instead.
I say "hammers" plural even though one will usually work. I learned to do it from dad where he'd put one hammer (the big mini-sledge type) up along one side of the knuckle and whack the other side with the other hammer.
Basically just to take some of the side loading off of the part being smacked, but also in theory to add some shock-wave effect as the vibrations bounced back and forth through the part. Don't know if that actually works better in all situations, but it has for me so far.
This was usually with smaller car-sized parts though, whereas the bigger truck-sized stuff isn't likely to be harmed by a few good whacks up side the head by a single hammer.
It is definitely stress relieving though, to take hammer to metal.
Paul