Chatter when turning, Differential?
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New User
Joined: Jan 2005
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From: Tacoma, WA
99 EXPDN- Chatter when turning, Differential?
I have 99 Expedition. I don't know the entire history of the vehicle, but have driven it for the past 20,000 with 75K on it now. There is a chatter noise coming from the rear end when starting from stop and turning left or right when accelerating. Never does this going staright. I read somewhere on a recall site that the 99 differential will experience this problem.
Has anyone had this experience and, if so, what is the cause and how much was the solution?
Has anyone had this experience and, if so, what is the cause and how much was the solution?
Last edited by vyates1; Jan 13, 2005 at 11:12 PM. Reason: to include yr/model in topic
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Joined: Apr 2004
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IF you have a Limited-Slip axle it could be as simple as needing to add a 2 or 4 ounce bottle of Ford Limited Slip Friction Modifier to the axle. Need to look at the metal id tag on the rear axle cover for the axle ration code, it will read something like these listed below:
373 3.73 3.73L L373 350 350L 3.50L
This is the axle ratio and if it has the " L " designation it has the limited slip axle that has friction/clutch plates that require the friction modifier additve. The friction modifier additive gets depleted and fresh additive needs to be added to the axle over time. Any time the gear oil is changed a bottle of additive neeeds to be added back to the axle. Some people call it "growling". It typically starts as a low growling sound during low speed turns when the oil is at ambient temperture and as the oil heats up the growling goes away. Eventually as more additive gets depleted the growling is noticable at any temperature when cornering. When the vehicle is going straight there is no slipping of the limited slip clutch plates in the rear axle so there would be no noise.
Hope this information helps.
373 3.73 3.73L L373 350 350L 3.50L
This is the axle ratio and if it has the " L " designation it has the limited slip axle that has friction/clutch plates that require the friction modifier additve. The friction modifier additive gets depleted and fresh additive needs to be added to the axle over time. Any time the gear oil is changed a bottle of additive neeeds to be added back to the axle. Some people call it "growling". It typically starts as a low growling sound during low speed turns when the oil is at ambient temperture and as the oil heats up the growling goes away. Eventually as more additive gets depleted the growling is noticable at any temperature when cornering. When the vehicle is going straight there is no slipping of the limited slip clutch plates in the rear axle so there would be no noise.
Hope this information helps.
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New User
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From: Tacoma, WA
I looked for the id tags mentioned and found two tags. One has numbers that don't resemble anything near the ratio numbers mentioned and the other specifies synthetic oil only. Are these id tags generally mounted with one of the bolts holding on the cover? Does anyone know?
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Joined: Jan 2005
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From: macedon ny
look at the tag on the drivers door there is an axle code there. I believe that if there is a letter in the code it means limited slip. This does require special syn. oil and the modifier. The oil is pricy but the modifier is not too bad. I would add the modifier , find a empty parking lot and do five circles left and five circles right . this should fix the problem.
