Hi all,
I have a 96 Grand caravan SE with 184K miles on it.
I recently replaced all the tires, the shocks and struts, along with various other parts, non suspension related.

The van has had a 'bumping' noise that almost sounds like a flat tire (increases at higher speeds, etc) for some time... I thought the new tires would correct the problem but it has not.

Since this vehicle is front wheel drive (but I'm fairly certain that the noise is coming from the rear) I'm at a loss for what to check.

Perhaps it's just a stupid question, but if anyone has experience with this and can suggest something or point me in a direction I'd greatly appreciate it!

Did you check the rear wheel bearings?

Have you looked to see if your exhaust pipe is bumping against the body somewhere in the back and making this noise? I have a similar problem and that is what I suspect.

what about you spare tire..is it tight?

I had that same problem and it ended up being the wheel bearing. I think if you jack up the car, you'll probably find that the wheel has a lot of play in it. Then this means the wheel bearing is bad.

Good Luck!