Popping sound when accelerating 2007 4.6L Explorer

[rober01c]

I need guidance on where to go from here. When i accelerate hard, I hear a popping noise that seems to be coming from the driver's side wheel area. This occurs in several different gears and regardless of whether I have 4X4 Auto or High engaged. I replaced the back two tires a few months ago and while I believe this was happening before then, it may have started at the same time.

From everything I've read I either need to have all 4 tires be the same, or I have a transfer case problem. My dilemma is that if I go to Ford they want $250 just to diagnose the problem, and since my experience with their service is not positive I do not want to incur this expense if all they're going to tell me is that I need to replace all 4 tires.

So If it is MOST LIKELY just a tire issue, do I need to buy 4 new tires or can I buy the same ones I put on the rear for the front? I have about 2500 miles on the tires in the rear.

Thank you so much in advance for your help.

 

[rober01c]

Additional detail

Forgot to mention that accompanied with the popping sound is a loss in power almost as if the engine is knocking, but it feels like the tires are slipping.

 

[waskly]

does the tracking control light turn on when this happens?

 

[rober01c]

When this occurs the tracking control light does not illuminate, nor are there any other warning lights.

I have tried, however, turning off the tracking control by pressing the squiggly car button and this does not change the effect.

 

[rober01c]

One other thing - I've measured the circumference of the tires front vs. back and they are within an inch or so of each other.

 

[waskly]

One other thing - I've measured the circumference of the tires front vs. back and they are within an inch or so of each other.

an inch is pretty big.

thought you had 4 matching same tires.

honestly i would put 4 tires, since i cant see them, they can take a variation but not to big. an inch in circumference is huge.

 

[rober01c]

The tires both front and back are 245/65R17 which have a circumference when new of 92.8 inches. I replaced the rear tires about 2500 miles ago. By my calculations the 1" difference in circumference equates to less than 3/16" difference in tread wear between the front and the back. Not sure if that would be significant enough to create the condition I am experiencing.

So - new tires or subject myself to the whim of the dealer?

 

[Ford Explorer9]

What about a general mechanic? If it is a simple problem that is easy to find a good mechanic will do it for free, and at most it would be around $75 for a diagnosis.

If possible can you try to describe the popping sound a little more?

 

[rober01c]

The popping sound is somewhat muted, not clicking, not sharp or metallic, not a heavy whump, nor is it grinding or flapping. It's a sound like a gear or a serpentine belt slipping, like a bone popping out of joint. It makes about five to ten of these when accelerating. I can attenuate the level up or down depending on how hard I accelerate, or even make it go away altogether if I baby it.

 

[rober01c]

Buehler, Buehler? Anyone?

 

[waskly]

im going to say you need 4 of the same tires.

we can argue all you like, but i'm probably 99.99999999999999% wrong in your eyes. but i cant see or hear it, so with that said, you need 4 matching tires.

your abs system could be more sensitive or less. in any case. they have to match, make/model/size/wear. when they dont, these trucks act / make all sorts of noises and driving conditions.

 

[Town]

The tires both front and back are 245/65R17 which have a circumference when new of 92.8 inches. I replaced the rear tires about 2500 miles ago. By my calculations the 1" difference in circumference equates to less than 3/16" difference in tread wear between the front and the back. Not sure if that would be significant enough to create the condition I am experiencing.

So - new tires or subject myself to the whim of the dealer?

I would not buy new tires for a 3/32" wear differential between front and rear tires without trying what Ford suggests: move one front to the rear and one rear to the front. That will give the wear difference across the axles instead of across the transfer case. ABS should not complain about that.

Supporting information:
1. The 4x4 systems do not like differing sizes of tires or significant differences in tread wear between front and rear tires. So 3/16" difference between the front and rear tire diameters is problematic and the transfer case will make noise.

2. Here is what the Ford manual says: "CHECK tire tread wear to see if there is more than 0.15 mm (0.06 in) difference in tread wear between front and rear. INTERCHANGE one front wheel and one rear wheel. ROAD TEST again."

3. A 3/16" diameter difference is 3/32" tire tread wear difference which is .093" about 50% more wear than Ford specify. The ABS is not as sensitive as the transfer case to differences in diameter so will not object, since it does not object to the current front to rear difference either.

Good luck.

 

[rober01c]

All - thank you for your insights. I replaced the older tires so that I now have the same tires all around. No more popping!

 

[waskly]

All - thank you for your insights. I replaced the older tires so that I now have the same tires all around. No more popping!

glad you got it resolved.