When it makes the sound my foot is pressing the throttle down far for about 1 second.

Sounds like some splines are slipping, or chain is slipping inside the transmission, or the converter is not engaging the input shaft properly and is slipping and grinding under heavy torque.

Says AX4N on transmission pan, but I think 2007 Freestars have 4F50N transmissions.

I need the dealer workshop manual, anyone know where to get the PDF? I paid for a Haynes, but it has no info about the internal transmission.

 

You can see the tire shake the first time it does it. I have a feeling I will be pulling the transmission. I just bought this van, and when I test drove it I floored it to see if the transmission had problems and it didn't do this. I have a filter and fluid and gaskets and silicone and wipes and soap to do a change and to see if any big metal pieces are inside the pan.

 

What does the wheel on the other side of the vehicle do?

 

Good question. Night time right now, will try tomorrow.

 

I just tested it, it does it in all 4 gears. It didn't do it at full throttle from a dead stop, but I only did it once.

 

Same thing, shakes on right. I hope it's just the axle. I have a new left axle, seal, and tie rod end for the left, I'll hopefully get it done tomorrow. And tranny fluid and filter change.

 

It's weird, I went full throttle 4000-5000 rpm up a freeway onramp and it clacked at first then stopped clacking and accelerated and shifted fine once the throttle was wide open and the rpms were up.

 

New axle, new tie rod end, tranny fluid and filter, engine oil and filter.

Still doing it ....

Alot of fine metal on magnet in tranny pan, no big chunks. I just got this vehicle so idk how long previous owner went without tranny fluid and filter change.

 

View of the Intake Runner Manifold Control mech while driving, GoPro and a flashlight clamped to the AC pipe, when the engine moves back my foot is half way down on the throttle, that is when the gun noise happens, the IMRC seems to lag behind a couple seconds after I take my foot off, is it supposed to do that? This IMRC tech is new to me.

 

Now that you have narrowed it down to an engine problem, can you get the engine to do it in gear with your foot on the brake? Also take a close look at the vibration damper(crank pulley). Is the engine cutting out at a hi rate of speed and load?
I didn't believe it until I saw it , but I did see a similar situation where the engine ran with a broken crankshaft. Not to give you needless worry, but at this point I don't have any other suggestions without being there.