transfer case - always working?

[Oxygen]

just a quick question out of curiosity.. is the transfer case on my 00 XLS 4.0 OHV always working when i'm driving around just in 2WD mode?

or does it only engage and start to work when i put the truck in either 4WDHI or 4WDLO?

thanks!

 

[Verno]

BOTH. Ok, the purpose of the T/C is to Transfer power from the transmission to the selected drive wheels be it the rear shaft or both shafts. What isn't working in 2WD mode is it should not be sending torque to the front drive shaft.

 

[Oxygen]

ok thanks! good to know! i did a transfer case flush about a month ago.. the fluid inside the transfer case does not blend or get mixed up with the transmission itself correct?

since the transfer case is sealed the fluid that i changed on it just stays in the transfer case right?

 

[gijoecam]

BOTH. Ok, the purpose of the T/C is to Transfer power from the transmission to the selected drive wheels be it the rear shaft or both shafts. What isn't working in 2WD mode is it should not be sending torque to the front drive shaft.

Not true on a second gen... It's not as simple as on or off.

On *some* second gens, you don't have a true 2 wheel drive (your '00 should fall into that category). You have 4AUTO as the default setting.

The electronic controls vary the duty cycle of the transfer case clutch coil. At WOT, for example, it'll ramp up the duty cycle so that the case is evvectively locked whether it detects wheel slippage or not. At part-throttle, it'll dial the duty cycle back some. When stopped, it'll dial it down to a minimum duty cycle. Those that have installed a lighted switch for the brown wire mod can see evidence of that by the change in intensity of the light in the switch as visible evidence of what the service manual info states.

When slippage is detected, it automatically ramps up the duty cycle of the transfer case clutch coil for a moment, then backs off, checks for slippage, and repeats if necessary. When working properly, it'll react before you realize it needs to.

 

[treydestepheno]

Hi, I have a related problem. the explorer is a 1996 xlt.

We were getting this rumbling sound coming more or less from under the driver's seat, and it would disappear when we went into 4wd auto. we placed the rear end on stands and with the selector set on 2wd, we put the explorer into drive and sped up the rear tires to about 40 kph. the rumbling appear to be originating from the front driveshaft... which is spinning in 2wd!!


I did some reading here: http://www.explorer4x4.com/controltrac_mod.htm

and here http://www.explorerforum.com/forums//showthread.php?t=182071
"This is the front side. The splined shaft is the input, and the round connector hooks up to the driveline to the front wheels. They turn together only if the clutch is engaged inside the transfer case."

I read enough to assume that this shouldn't be happening. Is something wrong with the transfer case? maybe the clutch? maybe a wire somewhere is loose? I'd really appreciate any help that the pros in here could offer.

also, nothing else seems to be wrong, no flashing 4wd lights, no problems engaging 4wd auto or 4wd low. Also, the CAD seems to be working fine since the front tires do not get any power from the front shaft as it spins. Again, your help will be greatly appreciated.

the TC model is "F57A-7A195-CA", which makes this transfer case a part-time electric shift model (I think). and the selector on the dashboard has 2wd, 4wd auto and 4wd low.

 

[Oxygen]

ya you're right gijoe.. i have 4AUTO

i understand how the transfer case works now, thanks!