Making a DIY gearbox lifting frame for a floor jack

I wanted to lift out the gearbox of my e36 BMW 318iS from under the car. The easiest way to do that is with a lifting frame on a hydraulic floor jack. Such frames can be bought, or there are a number of videos on Youtube showing how to make them. This is my version. I just used some old rusty rolled steel channel I had lying around.

The design could certainly be improved. This did what I needed.