Just drove home my new (old) 1997 5.0L AWD - transfer case issue?

[ELeBlanc]

Just picked up my new used Explorer with 100k. My previous was a 2002 Explorer 4.0L.
So the 50 mile trip home was my first experience and it feels very different than the 2002. Its also my first experience with AWD. So - no I don't think I'm paranoid but I am trying to figure out what the new NORMAL is with the 1997 V8 AWD. Thanls in advance.

So 1997 feels like it has a bigger engine just waiting for you to step on the accelerator - but when crusing along on the road it feels more like its lagging or not free rolling waiting for you to put your foot back on the accelerator. The 2002 when you took your foot off the accelerator on a highway would continue moving with gradual loss in speed. I didn't think of this analogy until just now sitting at the computer and not driving but the 1997 feels like when you take you foot off it slows much faster. I don;t know this is true but this is how it feels and this is what made me wonder if its an issue with the AWD or this is just the way they feel or the way old ones feel.

then I found this (edited) in a thread on the site and it does feel like more like a manual transfer case in 4WD but maybe that is normal?

How do I know if my viscous coupling failed?

it's a little harder to tell. It can almost be like a driving a manual t-case in 4wd all the time. We all know this is bad on the driveline. Yes, it can cause the driveline to bind. This driveline binding could cause vibrations in the vehicle, regardless of speed.

 

[koda2000]

As I own both an AWD V8 and multiple 2WD V8's I can tell you that the AWD feels heavier than the 2WD (which of course it is). I can also feel the extra weight in the steering. Other than that, there's very little difference in the feel of driving the AWD. Check your tire diameter and pressure. The AWD is sensitive to unmatched tire diameter. The owner's manual says something like 1/32 of an inch (which frankly sounds ridiculous) but I had to use a spare tire with a significant difference in diameter just to move the truck off the road after a flat without having a flat spare. I found that the truck would barely move with the smaller tire on the front. Once the flat was repaired and the correct tire reinstalled, it was back to normal.

The AWD uses a viscous coupling in the t-case (center differential). Power is normally distributed with 35% going to the front wheels and 65% going to the rear wheels. When different tire speeds are sensed the viscous coupling heats up and stiffens, sending more power to the front wheels. If you have different tire diameters, the wheels don't spin at the same speed and that's interpreted as slippage. It's a bit like driving in 4WD on dry roads.