So this is gonna sound crazy and I'm sure anyone who looks at this thread is gonna have an interesting take on this.

I own a 1999 F-250 SuperDuty 5.4L and starting a few days ago I had put my truck in park when I got home and heard a loud whining noise that I knew to be the starter. I thought, well gee time to replace that part and get on with my day. So I went and got a new starter replaced the old one and when I started my truck I got scared. The key was only in the "On" position when the truck started. I personally never heard of this happening so I started troubleshooting. I then replaced the starter relay solenoid that is on the passenger fender. Not the issue. So I figured it was an ignition issue. I know at least 2 things. 1) The whining noise is the starter however not the issue. 2) It's constantly getting power. So I went into my column and took out the ignition switch, the little white box underneath the column with the with the multiple position toggle. That wasn't it either, so I then replaced the Key and tumbler and it wasn't that as well. I am now completely and utterly lost. I talked to my brother who is a little more experienced in the repair department than I am, and he thinks it could be something called the Shift Tube Assembly that is mounted inside the steering column. I don't know if that's what it is or not but I have no idea how to even go about getting that out with deploying the airbag or even how to take the steering wheel off. If anyone has run into this issue before or knows someone who has and the steps taken to stop this problem I would be extremely grateful for any advice, tips, and solutions to this confusing issue.

Thanks very much for taking the time to read this thread.

Justin Toshi

 

Why would you suspect the starter or making a whining noise when you put your truck in park? I'd suspect the transmission.

As for starting nw when you turn the truck on, go back to the last thing you changed before you notied the issue.....the starter.

 

The noise I heard was that of something rotating very fast I guess I should've said suspected but I thought since my truck only idles at 1200 rpm in park which is too high a speed for the start to spin at I assumed starter. I put the new starter on and reconnected everything the way I took it off I don't see how the starter would be the issue at this point. I know it keeps getting power so it could be an electrical issue but I already listed the steps I took trying to figure it out.

 

I don't think so Stuart. The starter turns when it gets power and stops when it doesn't; there is nothing that can fail in a starter that could possibly cause it to engage without turning the key to start.

Unfortunately I don't have a clue where to go with this. I'm not sure about the OP's truck, but if this were happening to my Excursion it would have to be the ignition switch.