2008 King Ranch 4wd 72000 miles. It's been doing this for a couple years and I don't know how to describe it any better than above. Any idea what it is or how to correct it?

 

The ABS system runs a dynamic self test when you first start out after a power off.

 

It's supposed to do this? Wonder why I didn't notice when I first got it.
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Thank you for your reply. So it's supposed to do this?

 

You sure it isn't limited slip clutch chatter? You will get that if you are turning when starting off if the fluid needs changing.

 

<br />This would help explain why it's every take off even when warm, stop lights in town, etc. I was told the fluids we're changed when I purchased it. In this instance, is it preferable to drop the pan or just swap fluid?

 

I'm talking about the differential, it doesn't have a pan.

Does it chatter if you have the wheels straight? If so, it's probably not the issue. However, with 72k, it wouldn't hurt to change it. It takes 75W140 synthetic gear lube with a bottle of Ford XL-3 friction modifier.

Look on your door jamb sticker, what is the AXLE code? Should be 2 numbers or a letter and a number. If it's 2 numbers (i.e. 19) it's not limited slip and that's definitely not your problem.

 

I'll have to look after work. Thanks so much for the info!

 

Something else to check might be the tone ring on the hub. Had a broken one that sent the abs into a frenzy at low speed.

 

Could be the parking brakes are locking up on the rear rotor or dragging.

 

I think you need a friction modifier in your differential.

 

Look at post #7........

 

Axle code is B6.
it does it less when the wheels are straight and a lot more when turned.
I don't believe it's the parking break, last weekend I replaced the pads and rotors on the rear axle.
Any idea what a "jiffy lube" kinda place would charge to replace the fluid in the front, rear and tranny and if this would currently the problem?

 

Just get the rear diff fluid changed with the proper friction modifier added first and see what that does. Very likely that is the problem.

 

B6 is 3.73 limited slip.

As I said, 75W140 synthetic with Ford XL-3 friction modifier. Should cost you about $150 to get it done.