2001 Expedition Eddie Bauer, 199, 499 Took her out on the freeway got up to about 55 and it was like the rpm's dropped, (like it was cutting in and out- but not like a misfire) then recovered. Then next day again at around 55 it felt like the tranny was not engaging/slipping and the rpm's raced on tach. Then back to normal. I pull a 21 foot Bass boat, so it needs to work a little.


Ther second issue, is that I can't figure out if the 4wheel drive is dis-engaging. I have a a switch on the dash, I can switch to 4low and it does, but little difference between 4H and 2 wheel. Jacked the front end up so both wheels off the ground, started her up and when I hand turned the front wheels the axles turned? iS THIS SUPPOSE TO HAPPEN?

 

That depends on where you have the selector switch set.

 

The switch is in 4AWD position. Are the front axles suppose to turn when both front wheels are off the ground and the motor is running and in neutral? Or just when it is in drive?

 

In A4WD the front axles get powered when rear wheel slip is detected.

 

I have to guess at what you are asking, so be patient, cause I may be wrong:
I think what you are asking is that, should the front axle shafts rotate when you manually rotate a front wheel (while the selector switch is in A4WD, engine idling, and tranny in neutral).
I don't believe your 2001 has IWEs, which lock and unlock the wheel hub from the front axle, so yes, the front axle shafts always rotate when the front wheel rotates.
And, the front driveshaft should rotate when the front wheels rotate when in A4WD, as the electronic clutch within the transfer case is disengaged.

If your slelctor switch on the dash has a 2H position, AND you put it in 2H, there is a slave cylinder in the front diff that automatically disengages (whoops I'm drawing a senior moment here, but I think it) disengages the front axle shafts from the front diff.
But the front axle shafts will still (always) spin with the front wheels.

Perhaps you are coming from the F-150 side of things?
Hope I didn't make it more confusing.