Have a 2002 4.6L 4x4 Explorer. My understanding is that in auto mode it will sample wheel slip and "seamlessly" engage the front axle. Well, it feels as if the engine is missing when it starts to slip and tries to power the front end. It's sort of like it samples the slip about 5 times a second and you feel every one. Basically, it is not seamless, it's distracting. I know it's not the engine because as soon as I press the 4x4 button the "miss" quits. Is this normal or is this warranty time?
I have the same vehicle. I've "gunned" it a little in the snow and the rear tires spun for a split second and then it gripped with all fours and accellerated pretty good. No complaints on my end. Maybe there is a legit problem with yours. Have it checked out, it's free.
I had a 2000 4.0l and when it was in auto if I caught some snow it would definately thump in and out of 4wd, as it caught traction it would disengage and then it would slip again and re-engage, apparently this is normal. I drove mine for 100k and never encountered any problems with it.
Does your vehicle have any form of traction control? That could cause the engine to retard (to reduce wheel spin), creating the situation you're describing. If you do have traction control, try turning it off to see if the problem goes away.
Our 2002 Explorer has the same jerking action (I think that it is kicking in and out of 4wd) when travelling at slow speeds or starting out, but if you accelerate more it seems to stay in 4wd.
I normally select the '4wd high' if I am driving slowly in slick conditions to head-off any damage that this jerking may cause to my drivetrain. It definitely doesn't seem 'seemless'.
My wife only has 46,000 miles on it so far, but I hope she can get at least 100,000 more before she is ready for another one.
My 2003 explorer 4x4 does exactly the same thing. The first time 4wd engaged was on some snow and I wondered what the heck the big jolt was. Seems to be only at low speeds I get the jolt. At > 20 mph its prety smooth, but still very different to what I was expecting - I think Ford could be a bit more up-front that its not "like AWD".
I posted earlier and stated that I too had a '02 XLT V8 Auto, and I don't have any of the mentioned problems with the 4x4Auto. Well, it snowed pretty good the other day and I really got a chance to test it again. I can say with a good degree of certanty that I don't have the problems mentioned. I stomped on that thing dozens of times, in soft snow, packed snow, slush, etc... no issues. The only time it made a jolt/noise was when my rear tires were in snow and my fronts were on the pavement. I think that's to be expected though. Hope my input helps.