Uh, what to do if the jack handle comes off while jacking up car.

Another fun experience working on my car. So I was jacking up my car from the diff and the darn jack handle came off while doing so. I don't think I had it tightened down enough. So now the rear of my car is in the air and the darn jack is holding it up... not exactly sure what to do. I took the spare tire jack and jacked up one side to get it higher, but the jack itself just clicks even higher...

I got it :) OE floor jack to the rescue

BTDT.

A shorter handle and lots of strength. I've used extensions, a breaker bar, etc...

I guess you can't reach the release valve to let it down? You could put some stacked wood against the tires and try to drive up and off the jack.
First one long board, a gap, a second shorter board, etc. to make like a ramp.
Or get one of those plastic ramp things and do the same. It would work so long as you can get traction. The jack would just drag along on its wheels.

You sir, need a second hydro jack. See if a neighbor or buddy has one.

I was able to raise it with a second spare tire jack.

Devise some way to get the "lever" down far enough to reinstall the handle and tighten the set screw this time.

I'm still laughing from reading the title.

BTDT as well. The crappy scissor jack works in a pinch.

or

block up the wheels (jackstands) and use a socket to relieve the jack pressure.

That jack looks a lot like my HF Jack. Mine comes down DAMN fast if I'm not ultra slow about its release.

Jack stands under both sides of the axle and then find a ratchet and socket that will grab the release shaft, which I'm assuming is square. Release the jack really slowly and get your hand off the ratchet.You should be able to pull the jack out and start over.
Edit: I just checked my old HF jack and the shaft in it is a 12mm hex.

Ahhh, that makes sense that the jack shaft can be used also with a hex. This is the second time I've ever used a jack. Fun times.

I had this happen while working on the front of the GTI. I opened the hood and realized that I could just kick the jack over a little and stick the jack handle through the engine bay between the trans and radiator.

Ever since then, I make sure the retainer bolt is tight! And not missing.

I've experienced this. Grab it with big channellocks and pull it down enough to get the handle in.

This is really annoying if said jack is under the rear diff of a D350....and it's the 3rd time that weekend it's happened. (I really need to put a bolt in that hole that's designed to hold a bolt to stop this from happening)

I don't think I have ever had that happen to me. Going to make sure the handle bolt Is tight from now on.