That is a lock system that can be removed with the key,so you can install the tire tool in it and let the spare tire down to the ground.
It's under the back bumper. You will see a small hole around the bumper area. You will need a tool to spin it down. It's attached by a cable.
Not that difficult but the 350, 5.7Liter has hydraulic lifters and you must be sure the oil hole is lined up with oil hole in block
There should be tools under your passenger seat that you need to do this. Then there should be a hole above your rear bumper that you put the tool in and spin it to lower the wheel.
you have got to change the hole bumper
with your jack handle and there should be a little package in there with a short piece that hooks on the end of jack handle then slide thru hole in bumper and turn
Look for the hex socket bar under the seat. Find the hole through the rear bumper and insert the socketbend of the bar. With the ratcheting handle, turn to lower the spare.
The spare tire on a 2002 Chevy Venture is located under the vehicle, ahead of the rear bumper. You must attach a folding wrench to the extension and insert a chisel through a hole in the rear bumper and into the hoist shaft. When you turn the folding wrench counterclockwise, the tire will lower. Keep turning until the tire is low enough to pull out from under the vehicle.
If you look at the back bumper by the license plate you will see a small black plastic cover about the size of a pack of smokes. Pop it open and you will see a hole in the bumper, Then put the tire tool in that hole and turn it counter clockwise and it will let the spare down. If it will only lower a couple inches then the safety hook mechanism is rusted or corroded. I had to squeeze in above the tire and push the hook mechanism in to get the tire down. After it was down I took a metal cutoff wheel and sawed the hook off. Now i don't have any problems.
There is a hole under your tail gate, between your bumper.. you stick you jack handle in it far enough to turn the cable let down peace that's under there... this will lower your tire down....
Key Hole - 2008 was released on: USA: January 2008
On my 1995 Ford Explorer , to lower the underbody spare tire , I open the liftgate and the access hole is located above the rear bumper at the center of the bumper ( I assume your Ford Aerostar would be similar )
The Hole Story - 2008 was released on: USA: May 2008 (Tulane University)