1996 Cherokee new owner--a couple dumb questions

Hi, everyone;

I just bought a 1996 Jeep Cherokee. It's got the 4.0 liter
high-output inline 6 cyl motor with automatic transmission. Of
course, it didn't come with an owner's manual. It's been a long time
since my last Jeep, so I have a couple of questions that I'm hoping
someone can answer.

1--The 4WD shifter has four positions, 2wd, 4wd part-time, 4wd
full-time, N, and 4lo. I guess I understand the differences between
part-time and full-time 4wd, but I don't know if this is a
shift-on-the-fly transfer case. Is it?

2--There's a button on the dash marked "Extended Idle". I'm making a
guess that one should depress that button when allowing the Jeep to
warm up or something. Am I close to right? Otherwise, what's it
for???

Thanks, folks!


--
screwem