Years ago, before I found out about the glued u-joints, I broke a 6" vice right in the middle of slide trying to get one out without heat.
Broke right at the thickest part. A 6" cast vice. Yea, it was older than dirt, but even still.
The driveshaft was undamaged & the U-joint was STILL in there. Hadn't budged.
Pretty good explosion when it let go. I jumped. Buddy ducked. Nobody hurt.
There was two of us involved. Just goes to show that smart-ass kids really don't know everything, even when there's two know-it-alls combining their 'immense' brain power.
"Tighter. Tighter. Put a pipe on that vice's handle. Now crank it TIGHTER! Need a BIGGER hammer! C'mon, hit it harder. It's just a U-joint. We will not be defeated!"