I suspect that the radiator cracked first, then the steam shorted out a few plug wires causing engine shudder, which you felt as the shaking.
I blew the upper radiator hose on my 2002 Dakota and was lucky to be making a turn when it happened. Going so slow the steam was noticed right away…had I been going 50mph the steam may have not been noticeable and I may have overheated and done engine damage.
Hopefully the same happened to the poster…
I, personally would never buy a used radiator. You can probably get a brand new one for under $150.
Yosemite