2003 Explorer V8, jerking problem

[1965Dax]

I have a 2003 Explorer 4.6L, V8 and I feel a jerking feeling from the front end when driving at 40 mph and faster. This jerking feeling is not permanent it comes and goes, without something in particular that could be trigering it. While crusing on the highway, lets say... 60 MPH, the car feels like it is giving slight jerkin motions it even seems that comes from some imperfections on the highway, but it's not. It also appears when I let go the gas pedal.

[shorod]

Welcome to the forum!

Try rotating the tires from front to rear and see if the feeling changes or goes away completely.

From your description, it sounds like you may have an out-of-balance tire or a tire with a separated belt.

-Rod

[1965Dax]

Than you very much for the answer. It seems that the problem is related to the tires. I went to a Ford dealer and they told me that the difference in the tires circunference is causing that the 4x4 Auto is misreading this difference and trying to compensate by activating the 4x4. This is when the jerking feeling start. They told me to activate the 4x4 high when this happen just to verify. I did it and the problem dissapeared right away. Finally to resolve this problem, I have to change all 4 tires. Unfortunately it seems that this will affect the clutch...will see after the tires are changed. Any thoughts?

[shorod]

Seems reasonable, but why are the tires a different circumference? Is it from not following an appropriate rotation schedule, or where the tires replaced at some point in pairs rather than as a set? You want to understand the root cause so this doesn't happen again.

As for your question about he clutch, I assume you are referring to the transfer case rather than a transmission clutch. The continuous shifting in and out of 4WD could cause wear on friction materials in the transfer case, but hopefully this hasn't been going on for a long time, and the increased wear is probably not significant enough to degrade transfer case life.

You may want to consider changing the transfer case fluid and pay attention to the fluid condition as it drains, looking for signs of contamination, just to be on the safe side.

-Rod

[1965Dax]

The main reason seems to be the unappropriate rotation schedule. I don't know this for fact since I just bought it. In your opinion, what is the best schedule to follow for this?

I will follow your suggestion about changing the transfer case fluid and pay attention to the fluid condition. Best regards and thank you.

[shorod]

I think the typical rule of thumb is to rotate the tires every 5k miles, but few people (myself included) follow that.

I attempt to do all my own maintenance and every time that I am under the vehicle or washing it, I review the tire tread wear. If it appears that I should rotate the tires, I do, but don't really follow a "schedule."

-Rod