No need to spread it. Look at the frame, you'll see that there is a taper that goes inwards, where the crossmember mounts. You'll see what I mean by looking at the crossmember from the rear, towards the engine, you'll see that it has the effect of sitting in the frame like a wedge, so it doesn't fall out without bolts... this is why it's a pain to get it to come straight down.
The trick is to unbolt the crossmember, lift it up, and slide it towards the rear of the truck. There will be a cutout section on each framerail for you to use. Right there you'll be able to finaggle the ears of the crossmember past the frame. 10 minute job.