Vibration at 35mph

[03snkvert]

My wife and I bought a 2007 Explorer Limited in December and ever since I have noticed that while accelerating when the Ex gets to about 35mph there is a slight vibration in the drivtrain that goes away shortly after. This happens all the time, so we took it to the dealer (under warranty) and they said it was just something with the 4wd that matches up the speed with the front tires (differential) to the rear tires (differntial).

I am trying to get some input on this, because the vehicle is about to turn 35,000 and want to get this fixed under warranty if it is an issue!

Thanks for the help Corey

 

[jrford]

What did they say? Is the 4wd engaging? Have the tires been rotated? Are they the same brand and same size and age? I'd be careful a dealer would love to have you back out of warranty 6mos later. . i document as much as you can. . .

 

[03snkvert]

I guess saying it was with the 4wd isn't quite right, it is when the vehicle is just in the regular driving mode (all wheel drive) and at about 35mph, under acceleration I can feel a slight vibration through the steering wheel for a brief second.

When we had it at the dealer, they said it was something with the transfer case or something that is matching the speed of the front wheels to the rear, which sounds retarded because if the front wheels are the same size (they are) and the front and rear gear are the same, there should be no difference.

here is exactly what the dealer said:

"28367 vibration on driveline on heavy accel test drove veh and verified concern, found concern is normal operation for veh equiped with 4x4 auto, concern is cause by transfer kicking in on heavy accel to equalize front rear diff speeds. normal operation"

 

[SLVRTRC]

first thing i would do is check the tires get them balanced and rotated

 

[jrford]

follow this on page 2 they pulled some fuses to turn off the 4wd for testing, what does that do? Are you flooring it to get it to happen?
http://www.explorerforum.com/forums/showthread.php?t=247249

 

[03snkvert]

I will pull the fuses and check it out. This is happening under "normal" acceleration. I drove it earlier this week and you could just feel the slightest vibration in the steering wheel.

I am going to get it up in the air this weekend and try and measure the diameter of the tires. The Tires look like they are new, but the diameter could be throwing things off.