FRONT HUBS CHATTER? 2H - 4A STOPS THE NOISE?

[K-Clive]

Hi ALL

I have an odd(?) problem - enough about me!

2012 Expedition MAX - pulling a trailer, long drives (600km Toronto- Gore Bay) after about 2hrs, like it's on a timer(?) I feel a chatter
in the pedals, here what sounds like road noise, chatter, buzz... and it comes and goes, usually on uphills when pulling vacuum.
It seems to me it comes from the left front hub.
IF I switch 2H to 4A the noise stops and smooth sailing... I leave it like that for a few minutes and switch back to 2H and it's fine for a while and then
we go through the whole thing again. After a bunch of this activity, it seems to stop completely and we finish our journey.
I looked through the previous owner's service reciepts and there is a left front hub service just before he sold the vehicle.
It says: (In French) 2H chatter problem and they replaced a solenoid? -> Lock gauche selenoid du 4x4 en trouble P.C. remplacer lock + selenoid
Road test OK.

It's impossible to test drive this issue because it takes 2hrs of highway speeds pulling weight to produce the problem.

What is it actually doing when I swith 2H to 4A?
Is this a vacuum leak or electronics or locking hub issue?
I have heard FORD has a LOT of problems with this stuff on F150 & EXPY - the mechanics I taled to said: start replacing stuff until it stops doing it!

 

[99WhiteC5Coupe]

Hi ALL

I have an odd(?) problem - enough about me!

2012 Expedition MAX - pulling a trailer, long drives (600km Toronto- Gore Bay) after about 2hrs, like it's on a timer(?) I feel a chatter
in the pedals, here what sounds like road noise, chatter, buzz... and it comes and goes, usually on uphills when pulling vacuum.
It seems to me it comes from the left front hub.
IF I switch 2H to 4A the noise stops and smooth sailing... I leave it like that for a few minutes and switch back to 2H and it's fine for a while and then
we go through the whole thing again. After a bunch of this activity, it seems to stop completely and we finish our journey.
I looked through the previous owner's service reciepts and there is a left front hub service just before he sold the vehicle.
It says: (In French) 2H chatter problem and they replaced a solenoid? -> Lock gauche selenoid du 4x4 en trouble P.C. remplacer lock + selenoid
Road test OK.

It's impossible to test drive this issue because it takes 2hrs of highway speeds pulling weight to produce the problem.

What is it actually doing when I swith 2H to 4A?
Is this a vacuum leak or electronics or locking hub issue?
I have heard FORD has a LOT of problems with this stuff on F150 & EXPY - the mechanics I taled to said: start replacing stuff until it stops doing it!

There is an independent wheel engagement (IWE) electrical-vacuum solenoid and an inline check valve for the 4WD mounted on the firewall near the brake booster. They are common failure items.

Both are inexpensive, easy to see and reach, and can be replaced in 5-10, taking your time.

I suspect when towing, your engine vacuum drops causing the front IWE hubs to clatter, as they momentarily try to engage.

When driving in 2WD - the front hubs are unlocked and the IWE hubs are pulled back using engine vacuum. If the vacuum drops, and the check valve is leaking (or another vacuum line), it will cause the front hubs to try to engage to 4WD or 4A.

It is hard to inspect all the vacuum lines - the best method is to test each one individually with a hand vacuum pump.

You may want to replace the check valve and solenoid to see if that cures the problem.

There are several on this forum that are experts on the matter and I hope one or more will chime-in.

 

[K-Clive]

Thanks for that insight...

Looks like te solenoid/selenoid was just replaced so I am going on with check valve and vacuum line leaks.

If anyone else has thoughts, please chime in!

Thank in advance!

Cheers Clive

 

[mr_dave]

The solenoid and check valve are easy and inexpensive replacements that will usually fix that problem. Make sure any recently replaced parts are genuine OEM.

Ford F150 4X4 Diagnosis No Tools Required

You can get the new solenoid version Here-http://www.amazon.com/gp/product/B004SR7JVO/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B004SR7JVO&...

youtube.com

 

[JohnA]

Just rebuilt front end susp '10 Xlt. Found left IWE had corroded inside rubber vacuum sealing ring so that when there was vacuum applied, only part of of the ring gear would disengage, leaving ring gear cocked against wheel hub. This produced the 'chattering noise' on my car that K-Clive might also be experiencing. IWE did not appear damaged but condition was evident when removed. Changed both sides to Dorman non-vacuum (the inner ring is engaged to hub but solenoid is allowing vacuum to the transfer case switch to keep 4W disengaged) and no noise. Dorman says mileage may drop slightly because of continuous engagement (.1 MPG) but I have experienced slight gain since installation. FWIW

 

[K-Clive]

OK newby question here?
Where do I find the left/right IWE solenoid check valve etc?
I guess if you have to ask, maybe best to have a mechanic do it?

 

[K-Clive]

Ps JohnA:? How does your 2wd 4wd work with no vacuum?

 

[mr_dave]

OK newby question here?
Where do I find the left/right IWE solenoid check valve etc?
I guess if you have to ask, maybe best to have a mechanic do it?

It's under the hood on the driver's side firewall, behind the coolant reservoir.

Ps JohnA:? How does your 2wd 4wd work with no vacuum?

The transfer case will still switch between 4x2 and 4x4, however the front drivetrain (driveshaft, differential, and axles) will always be engaged. Basically it will be in permanent "4A" mode.

 

[99WhiteC5Coupe]

OK newby question here?
Where do I find the left/right IWE solenoid check valve etc?
I guess if you have to ask, maybe best to have a mechanic do it?

Here is a photo of the solenoid and the check valve on my 2015 Expedition Limited 4x4.

The solenoid snaps into the bracket with no tools (the electrical connector is the top gray one). The check valve is off white and blue (plugs in-line with the vacuum lines).

It is mounted on the firewall on the driver side, adjacent to the brake booster.

 

[JohnA]

Inside the IWE is a gear that meshes with the gear in the hub and with the gear on the outer end of the half=shaft. The inner end of the half-shaft is in the front differential. The vacuum-actuated solenoid shown in previous post is under constant vacuum from the engine when switch on dash is in 2W positionand engine is running, keeping the transfer case from engaging front drive shaft. The half-shaft, hub and wheel are one unit using this IWE, always turning but not engaged with the transfer case. Turning the switch to 4WA/4Wh or 4WL trips soleniod and 'stops' vacuum from reaching transfer case switch, which then engages, turning front drive shaft into front diff and producing '4W drive'. The only thing eliminated is the vacuum engagement of the hub with the half-shaft as it is now a 'solid' connection. The IWE also has a dummy port to re-connect the the vacuum line from the solenoid but its there just keep the vacuum line system intact and not trip any 'codes', I think. I hope I made this a little clearer. It does work and the Dorman part is available from RockAuto.
PS: I'm not a mechanic so please forgive the verbosity. John