My 2003 Expedition XLT 5.4 4x4 squeaks only when in gear. After a certain speed it goes away. I have hit the usual suspects like belt and tensioner and tested and deglazed all pullies. The U joints look fine and are tight. I just did the intake, plugs and coils plus all the high mileage maintenance: Oil change, air filter, change front and rear differential fluid, change torque converter fluid and change the trans fluid and filter. Under the vehicle the squeak sounds like it's coming from everywhere. With a stethoscope, I thought I had the squeak isolated to the passenger side catalytic converter. The cats were bad, so I had them replaced at a local muffler shop. My squeak is still there. The truck runs perfectly, except for the squeak! HEEEEELLLP! Thanks in advance. Greg in Flagstaff.
The attached files:
Squeak Driving: Low speed. Foot on and off gas. Squeak only with foot on gas and stops at about 20mph.
Squeak Stopped: Squeak stopped in driveway shifter in Drive.

 

I'd stay focused on the u-joints.

 

Thanks Alloro! The joints seem tight and it squeaks when stopped i.e. the drive shafts aren't moving. It's only in gear that it squeaks and it squeaks stopped or running. It seems that being under load in gear is the key factor. The engine and tranny mounts look fine, no oozing or torn chunks of rubber. The cadence of the squeak goes up when driving, but it does not match RPM. It gets a little faster and stays constant. I was leaning toward loose or cracked flex plate??? Your thoughts? Thanks! g

 

Ah okay, when you said, "My 2003 Expedition XLT 5.4 4x4 squeaks only when in gear. After a certain speed it goes away" I took that to mean it squeaks only when moving. Have you inspected the entire exhaust system to make sure a pipe or heat shield isn't rubbing on something?

 

Does it squeak stopped with gear shifter in Reverse ? Have you tried removing the serpentine belt and see if it still squeaks ?

 

Alloro: We went over the entire exhaust system, that was when we thought we heard the squeak in the passenger side cat. We did the temp test and the cats were bad so I replaced them. Everything looked fine in both in the initial inspection and checking the heat shields with the cats off. We went down the length of the shields with a pry bar to see if the sound would stop. Given that the sound did seem to come from the passenger cat, I am going to hit the exhaust manifold studs with the stethoscope this weekend. I guess they tend to crack...BUT you heard the squeak. I have never heard an exhaust manifold squeak like that, it was always more of a puff, puff, puff. Thanks for the ideas! I am open for ANY others you have! g

 

Hamfisted: I have replaced the serpentine twice along with the tensioner and idler pulleys. Deglazed the pulleys several times early on. Checked all others for play and squeak. Done the water test on the belt. Did the 303 spray on the belt. Ran it with the belt off to check the harmonic balancer and main bearing (there is also no major drop in oil pressure once warmed up).
It squeaks:
1. In Drive as soon as you shift while stopped.
2. In Reverse as soon as you shift while stopped.
3. While moving in R or D. It does seem to stop at higher speeds, but that could just be it being drowned out.
4. The cadence of the squeak goes up with driving, but not directly proportional to engine RPM.
5. It squeaks in 2H, AWD and 4 Hi. Haven't tried 4 low. All fluids had no sign of metal filings or really bad burnt gunk: both Differentials, Trans and Transfer. Truck runs GREAT!
Thank you for the ideas! I am open to anything you can come up with. I spoke to a transmission guy and he said maybe flex plate, but again, I have never heard a flex plate chirp like this. They are usually a 'whirring' or grinding. Same with the torque converter or transfer case.
Thank you! Greg in Flagstaff

 

At the risk of overstating the obvious...

 

I did have a mongoose in a fan shroud in Hawaii! It was a metal fan and I didn't see the mongoose til….you get the picture!

 

I also went out and ran the transfer case through all the gears: 2H, AWD, 4Hi and 4 Lo. At first the squeak was a little less in 4Hi and 4Lo, but it came back pretty quickly.

 

 

Thanks Mini1298! That was my first thought. I have gone over the U Joints 3 times now. Tight, no play. Today I listened with a stethoscope and the squeak is not coming from them. It happens driving and stopped when the U Joints aren't moving. I ruled out flex plate, torque converter, trans, transfer case, U Joints, oil pump and differentials. No squeak with stethoscope. I also hit the engine mounts and heat shields. I did seem to isolate it to the forward right side of the engine. I stethoscoped everywhere under the vehicle. Still driving me crazy! This week I am going to pull the passenger front tire and wheel well plastic to properly get to the exhaust manifold. I did see some corrosion on the underside. I want to verify that the corrosion is from the intake leak I just fixed. I will also check for rubbing etc. Thanks again! Greg in Flagstaff

 

Spent three hours this weekend with a mechanic friend (30 years experience) and we still couldn't find the squeak?!?!?!?!! I give up. We listened to and checked every major and minor system in the vehicle and it runs perfectly. The only thing we could find is that the engine torques a touch too much when put in gear. So it could be engine mounts, but we listened and no chirp on the stethoscope and we sprayed them with PB Blaster and no change in chirp. I'm going to drive it and see if it gets worse so we can find the issue. I will post if we ever find it.

 

How about body mounts, or suspension mounts? Have you checked them?

 

Body Mounts are a great idea! Thanks *2fords*! I will get out there this week. g