Vibration and Hum
Thread Starter
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Freshman User
Joined: Feb 2004
Posts: 26
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From: Atlanta
Vibration and Hum
I have a vibration and hum that starts around 50 and gets louder the faster I go. At 85 it is very loud. It feels like it is coming from the drive train. My Excursion is a 2003 with only 10,000 miles on it. I had Ford put on a new drive shaft and it did nothing. I was convinced it was the dirve shaft, so I took it to a specialist that balances drive shafts. They balanced it perfectly but no change to the vibration. What is weird is the vibration is worse when I let off of the accelerator and disapears when I'm really on the accelerator. I'm really upset since Ford doesn't know what to do to fix the problem.
Any help would be appreciated.
Thanks....Brian
(2003 Excurstion Limited, 4-Wheel Drive, V10)
Any help would be appreciated.
Thanks....Brian
(2003 Excurstion Limited, 4-Wheel Drive, V10)
Senior User
Joined: Aug 2003
Posts: 431
Likes: 0
From: East TN
If the FTE mod gods will let me, I will try to help you.
What you are most likely experiencing is body boom from imbalanced orbital revolution between the u-joints in your rear drive line. The shaft balance can be perfect, but if your u-joint operating angles are mismatched the effect will be one of aural dissonance that you can hear and then physically feel as the effect increases.
At first I thought this only happened with lifted trucks, but I have come to learn that some - I have no idea how many - stock trucks leave the factory with this imperfection.
Please do a search on measuring u-joint angles and you will learn about the dynamics of your drive line and the source of possible problems.
Good luck and come back with more questions as need be.
What you are most likely experiencing is body boom from imbalanced orbital revolution between the u-joints in your rear drive line. The shaft balance can be perfect, but if your u-joint operating angles are mismatched the effect will be one of aural dissonance that you can hear and then physically feel as the effect increases.
At first I thought this only happened with lifted trucks, but I have come to learn that some - I have no idea how many - stock trucks leave the factory with this imperfection.
Please do a search on measuring u-joint angles and you will learn about the dynamics of your drive line and the source of possible problems.
Good luck and come back with more questions as need be.
Thread Starter
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Freshman User
Joined: Feb 2004
Posts: 26
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From: Atlanta
Thank you for the reply. I just found out that I have a meeting with a factory engineer next week. I will take this information with me. Even though I have a warranty Ford will not attempt to fix the problem until the factory engineer looks at it. I hope he doesn't try to tell me that this is a normal characteristic. I know that it is not, I have driven a friend's 4-wheel drive Excursion and it is as smooth as glass. It sounds like if someone knows what they are doing that it may be easy to line up the U-Joint angles. If Ford will not come through I will look for an expert that does that type of work in Atlanta.
Brian
Brian
Senior User
Joined: Aug 2003
Posts: 431
Likes: 0
From: East TN
Read this before you go and you will likely be more prepared for the discussion than the Ford engineer. FYI - the propshaft is the driveshaft. It may take a couple of times to completely ingest it all.
http://www.vibratesoftware.com/html_...aft_Angles.htm
http://www.vibratesoftware.com/html_...aft_Angles.htm
