Modulator help
 

I have a 97 F250 with a 5.4. Where is the transmission modulator valve, and how do I know if it's working for sure?

What seems to be the problem?

Let me fill you in on what I have already been through with it. I had the notorious check engine light on and found out that it was the EGR flow, with which I wound up at the shop having the carbon cleaned out of it, and the solenoid replaced. That cleared that part up. The part that I am trying to figure out is a chirping sound that mainly happens when you first crank up. it sounds like it is coming from the backside of the motor by the firewall. It only makes this noise at start up. Soon as the engine idles down, that goes goes away, and when you drop it into drive everything is nice and quiet. It shifts fine, and runs fine other that annoying noise at start up. I have also changed the plugs and boots, but not the coil pacs. I probably also need to mention that it is a 4X4. I have been told by different people that it could be anything from a vacuum leak to a cam bearing. Other than the EGR problem nothing else showed up on the diagnostics. I am new to the sight and have already found a ton of helpful information.

On the modulator, there is none. This is an electric controlled transmission and not vacuum controlled like the old transmissions types.
If the noise changes like you hear , there very likely is a vacuum leak/bad hose.

Could be your strater hanging up. Does it happen every time you start it?

For the most part yes. If it has only been sitting for a few minutes it's not quiet as bad as a cold start. I did fail to mention that this problem already existed before I had the EGR problem fixed.