The other day I took about a 30 minute drive, mostly highway above 65mph (if that makes a difference). As I was slowing down and coasting into a parking lot I started hearing a noise like a hammer hitting metal. I pulled into a park space and popped the hood. It was really loud. Thought the truck was about to come apart. Thinking that something bad was about to happen I shut the truck off. I waited about a minute and turned it back on to see what would happen. No noise, so I drove right home. Drove it around town this morning for about 20 minutes and it seems ok.

After searching around the only things I can come up with are Injectors or the Torque Converter. Figured I go under the valve covers and torque everything down and see if anything was broken or just laying in there. I torqued about half the bolts on the drivers side. The one thing I did see was that the back injector (drivers side) was an AD, not an AE. Is this normal? Gonna try and pull the passenger side valve cover tomorrow.

If its the torque converter would I need to take it out to check it?

Anyway, would like to know if anyone thinks the hammer hitting metal sound is injectors, torque converter or something else. Thanks.

 

Probably your flex plate if it's really loud.
Injector knock sounds more like an injector dumping it's fuel all at once, making the diesel knock for that cylinder much more pronounced.

 

It was really loud. Is there a certain thing that will make the noise start, like when it warms up, at idle, something like that. I'd like to try and get it to make the noise again so I can pinpoint it a little better. Is it something that will just start making noise every now and then? How hard is it to change the flexplate?

 

Looks like a long lead injector. Completely normal for the late 99.5 though I got rid of mine.

 

Its normal for me not to have the LL injector or do you think that the injectors may have been replaced by the PO with all AD's instead of putting an AE in?

 

I have the LL injector also, somthing ford did to help with the starvation/pinging sound of #8 injector due to the poor fuel system design.

 

Any info on how to check the flexplate? If it is broken is there a write up on how to change it?

 

To check it you will have to pull the TC inspection cover and or starter, whitch ever gives the best view. You will have to turn the engine over by hand and look at the flexplate/flywheel all the way around, from crank to TC bolts. If you see so much as a crack, it is bad and can make a sound like a rod is knocking.

To change it, you have to pull the transmission.

 

whats the harm in driving it like this until funds are aquired to fix it?

 

If it is the flexplate, eventually it will break completely and the truck won't move.

If it is not making noise anymore, then it was prolly an injector noise. Since it went away and you can't seem to reproduce it, I don't think I would worry to much about it.