Question about AWD transfer cases

[threeputtpar]

Hi everyone.

One question about the transfer case in my Mountaineer - in normal driving, does anything inside the transfer case move? More specifically, are the gears and/or chains inside of it in constant motion when the vehicle is moving but the front axle is not engaged? I don't know too much about how transfer cases work, and I'm trying to determine if the fluid is getting worked around in there during the normal course of driving.

It's the factory fluid in there yet at 107k miles, and I'm considering changing it out this weekend because it seems that when the rear tires slip and the transfer case kicks in and puts power to the front, it doesn't disengage the front as well as it used to. My plan was to put new fluid in there and drive it for a week and change it again to get out the old stuff better, but I don't know if I need to find a snowy parking lot and force it to kick in to get the fluid to splash around in there and get it cleaned up good. I can force it to be in AWD full-time via the dash controls, but I think that would put undo stress on the system on clear pavement. Thanks.

And I have read up a bit on fluid for this transfer case and Ford's statement to use their special Transfer Case Fluid - XL-12. I'm pretty sure that it's just Mercon ATF without the Mercon label since they discontinued that spec some time back and can't put in on the bottles anymore. I'll probably just use very basic Dex III/Merc labeled fluid from my local parts shop, most likely Wolf's Head.

 

[Donald]

I do not think you will put undo stress by using the dash control. The only 4WD system I know if where that might be true is the Jeep with 4WD part time. 4WD part time locks the differentials so both wheels turn on an axle.

AWD should move the driven wheels to what it considers the best wheels to drive given the wheel sensors.

You can look up on the Amsoil website to see what fluid they suggest.

 

[exranger06]

The fluid is always being splashed around regardless if it's in 2wd or 4wd. You don't have to engage 4wd to "flush" it out.

 

[KD0AXS]

Do you have AWD or 4WD? There is a difference. IIRC, the AWD system in these is full time and has no control on the dash, and the 4WD is part time with 3 settings...Auto 4WD, 4WD High, and 4WD Low. The auto 4WD is normally in 2WD but automatically shifts into 4WD when the rear wheels start to slip, unless you manually shift into 4WD using the switch. You do not want to be driving on dry pavement in 4WD High or Low, as this can damage the transfer case or other driveline components.

 

[threeputtpar]

It has the AWD without the selector switch on the dash for 4HI and 4LO. It does have the ability to force it to stay in AWD, as opposed to letting it figure out when to engage the front wheels.

Our last Mountaineer had the selector switch, and was much better all around. I wish they would have stuck with that, but most dealers told me that the soccer moms didn't know how to operate the system and wouldn't respond well to dealers training them how it works.

 

[dwcopple]

I recently had an '04 Mountaineer AWD V8. I changed the xfer case fluid myself in the driveway with a Harbor Freight $4 pump. It has a drain and fill plugs. Piece of cake, used Castrol Mercon V. Old stuff was nearly black. Had around 90K on it when I changed it I think.