Auto 4x4 always on until 40mph...??

[rgbarbato]

Hi there, I have had my '07 XLT now for a few months and I love it, however I have noticed that the 4x4 seems to be active from 0-40MPH while in Auto 4x4... I can hear the moaning from the front diff when accelerating, then after 40MPH it stops. I unplugged the 4x4 computer module behind the glove box and it made the noise go away completely, what could this be?

I also noticed that if I let off the gas the noise goes away as well, but when I get back on it around 25-30MPH or so it reactivates the 4X4 again till 40mph. I have been reading around here and some say things about ABS rings being bad, or sensors in the transfer case... I am not too familiar with these trucks, are either of these easy fixes and is this a common problem? Thanks for any and all input!

 

[swetrid]

Tire concern, make sure they are all same tires/size/pressure. These are very sensitive to these.

 

[rgbarbato]

Tire concern, make sure they are all same tires/size/pressure. These are very sensitive to these.

yea, I completely forgot to mention that part. all 4 tires are brand new and the dealer measured them twice and said they are all perfect. thanks for the input, this was the first thing we checked (which is why I forgot about it already).

 

[paulyjsob]

My Mountaineer seems to be doing the exact same thing.

 

[rgbarbato]

My Mountaineer seems to be doing the exact same thing.

Let me know if you come to any resolution, I think I may attempt some troubleshooting with the speed sensors on the transfer case.

 

[Throttlejunkie]

Having the same issues

In my 2008 Explorer I am having the same issues. I talked to a Ford engineer and the maximum size difference you can have on any of the 4 tires is .5 inch.. I measured all 4 and the max I had was right at .5 so I swapped the tires and wheels off a 2010 brand new Explorer and I had the same exact issue. Sounds like the exhaust is grounding out on the frame until around 55 mph or so. Monitoring the AWD system, it is putting about 60% transfer to the front diff, way too much I would think, either that or there is an issue in the case, or diff. My 2006, was as quiet and smooth as silk. The only thing that is different between the 2 is the 06 had 16" wheels and Michellen tires and the 08 has 17" and Goodyear tires.

 

[DreadI]

same problem 2008 Mountaineer V8 AWD - engaging

I am having the same problem on a 2008 Mountaineer V8 AWD with 22,000 miles. I can hear and feel the front drive shaft engage during acceleration and then release at about 45 MPH. Under heavier acceleration It will stay engaged until cruising speed. The previous owner did not take care of the tires so I had new ones put on and it improved this condition but still very noticeable. This does not seem normal to me. Still under warranty so I will be returning to the dealer. Any other ideas?

 

[Throttlejunkie]

I had ordered a front drive shaft in wishful thinking that the driveshaft may have been unbalanced or balanced incorrectly. I haven't had a chance to try that yet, but I have used the Ford IDS tech tool to completely disengage the output to the front axle and the noise and vibration is completely gone. I was told by an engineer to then monitor the load of the engine. I am not sure what, if anything would command a higher load than normal, to force a higher percentage of front axle engagement.

 

[rgbarbato]

Sounds very familiar... I have had it at 3 different ford dealers and all say the noise is normal. The tires are all brand new with less than 4000 miles on them and even when they were brand new the noise never went away. I'm unloading this hunk of junk as soon as humanly possible, I'm so tired of ford not wanting to admit to obvious problems that many people are having, and continuous wasted trips to the dealer only to have wasted days at a time to be told I'm crazy and the problems are normal.

 

[DreadI]

Throttle junkie let me know how the drive shaft works out. I am thinking maybe it is normal, but if the drive shaft or U joints are not balanced, then it will be more noticeable.

 

[Beargap]

Have you tried replacing the speed sensors? If one has noisy signal on the rear drive shaft output from the transfer case it could be sending an intermittant signal that makes the computer think the rear is slipping and so it would send power to the front driveshaft. Speed sensors and electrical connections are a common failure mode.

=Vic=

 

[paulyjsob]

I was told by 2 techs that its normal as well. Its only evident right around that 2000RPM mark and is non-existent at other times.
My Mountaineer runs great otherwise and has an extended warranty. I'm at the point where if its not causing any long term reliability issues, I'm fine with it.

 

[Alan Lloys]

I have a similar noise on my 08 V8 mountaineer AWD which has basically the same system as the Explorer.
I actually ended up purchasing the shop manuals as I wanted to figure out exactly how the system is working on the Mountaineer as I felt the AWD designation was a bit misleading. After a lot of discussion on this forum I have it figured out after reading the shop manual and the patents for the system - even though there are some here that insist what I am reading is incorrect. :-(

Anyway under the 4x4/AWD (Mountainer V8 only) troubleshooting it is clear that the front will engage dependent on the throttle position. This is an engineered feature to minimize wheel slip under heavy acceleration. So the heavier you push the gas, the more the front clutch will engage.
I believe there is a speed input as well which will explain why it disengages at higher speeds.

I hope this helps you. So it is in fact normal that you can hear the front clutch engage under acceleration. however it should not give significant vibration or noise.

 

[TheXMan007]

Alan is correct. The GEM will sends a signal to the T-Case motor every time you accelerate. It is from a torque on demand sensor. Any time the computer sense that you require torque i.e accelerating, it engages the T-Case to make sure that you have sufficient traction. You can disable this. Without pulling any fuses. People call it the "brown wire mod". You can find a tread here to do this.
Basically what you do is just put a toggle switch on the torque on demand signal coming from the GEM to the T-Case. The wire is brown. That way you can turn it on and off when ever you want. I used a switch that has a LED on it. When I have the switch on, the LED is dim. But, when I hit the gas you can see the LED get brighter. It will go dim again when the truck senses that you are no longer in situation were you might lose traction. Usually around 45 mph. Also, when I have th 4x4 switch in 4High the LED is bright constantly. This switch really comes in handy if your are like me and plan on putting your X on a Dyno. Don't want the front end engaging then.

I hope this makes sense and satisfies your concerns.

 

[jmaurath]

So basically I have had the same issue in my 08 Explorer. After reading lots of stuff on here I did the following.

I removed the fuse for the 4x4 module under the hood. This turned on the "wrench" symbol on teh dash, but eliminated the noise completly. This verified to me that the issue in in the 4x4. I also noted that when I select 4x4 high the noise is constantly present. This leads me to conclude that the noise is becasue something is not right with the 4x4.

Now, I don't want to do the brown wire mod because I actaully want my 4x4 to kick in if the rear wheels slip.

So, can anyone offer tips or help with trouble shooting where the noise is comming from in teh 4x4. Should I check axles? gears? what?

Anyhelp would be appricated.

Thanks