Matt3989

Okay, so I've dug around a bit and read as many threads as I could of people with similar sounds, I can't seem to find anything that seems feasible, so I'll start a new thread. It's an 04 F150 5.4L Lariat with 170k on it.


The Sound: Creaking/Light Popping noise (not like a Universal/CV joint with heavy distinctive pops) coming from the rear while making right turns (wide highway right turns) while accelerating or going over bumps and potholes. It mostly occurs at highway speeds. It's not a consistent sound wither, the best description I can think of is that it sounds like pop corn popping in one of those aluminum stove top containers.


I also have a whistling coming from the front left of the truck that starts when I'm around 1800/2000 RPM's and not under load. (I know, everyone is thinking vacuum leak and the HDE's trying to engage now).


I've mostly read two diagnoses:
Motor pinging from bad fuel and I'm hearing it in the muffler - I don't believe this is correct for a few reasons, 1) since it occurs most distinctively when making right turns, 2) I believe pinging/knocking would set off a check engine light.


Or the HDE's trying to engage because of a vacuum leak, I've experienced this before, It doesn't sound like it to me. The sound does sound like it's coming from the rear, although I know that is easy to mistake especially trying to pinpoint it while driving at 50mph+




Anyone have any other thoughts? Experience this before? Any Suggestions? I think it has to do with the rear Diff, considering how many miles are on the truck and how the sound tends to manifest most when turning.

Mattloz

Open your rear diff and make sure there are no chunks of metal if you have a limited slip maybe the clutches wore off and are disintegrating and hitting the cover, the bad gas won't cause a check engine run the highest octain you have ( most likely 91) and run two tanks if nothing changes then it's not bad gas and while you use higher octain it actually good to run high octain once in a while ( I run high octain everyday 91) so night octain won't damage anything

Matt3989

Thanks, my next step is to pull of the differential cover, clean the magnet and inspect everything.


I don't think it's the fuel, any preignition would definitely throw a code. And running higher octane than necessary is a pet peeve of mine, the truck is tuned for 87, putting anything higher into the tank is just reducing the power produced and costing extra cash.

primalurges

Sometimes when the cats deteriorate they can sound like if there are pebbles in there bouncing around. The whistling is common. I've yet to see a post of anyone identifying the source, just a lot of guesses.