Well considering what the coin phrase of Opinions says........ 750@ idle is a touch high if warm, and a touch low if cold.

Listed in sig Our family 2000 5.9 (assembled Oct 99) idles @ 900 cold start in ambient of 45° or lower.
Cold start in ambient of 60° and up, the idle is around 800 and up, No matter the ambient temp the operating temp (210 on dash using a 185° stat) idle is 600 RPM.

The only reason I chose to pick that apart, is for what it's worth it could be a significant clue to an unnoticed issue beit for You or for Me.

I am Not a tranny guy really either, I understand why you would be nervous....but keep in mind these things were designed by Dodge, not NASA.
Transmission shops make their money mostly in labor cost because rebuilding a tranny is not all that expensive to do, even starting with a total gut out of the case.

Doing the Math below will prove that much.......and anytime you see $1800 for an OEM REMAN, that is without a freight calculation which will rapidly double or triple total cost.

1. a 46RE/47RE/A518 rebuild kit with raybestos clutches comprised of fresh metal and frictions both [every one you will need, including about 4 you won't] as well as every filter and seal you need ( and obviously a dozen you won't) can run you for $150 or less
2. the Gov pressure sensor switch and transducer (MOPAR OEM) can run you for $80 or More
3. OEM recommended replacement stall speed torque converter can run you for $200 or less
4. a new AT Pan (mine was rusted to hell) can run you for $ 45 or less, but more if going to the drain plug type
5. **New upper and Lower cooler lines can run you for $50 or less
6. **New brass cooler line fittings can run you for $80 or less
7. then the cost of enough ATF to fill 'er back up, which is 2 gallons varies widely (you don't use all of the 2nd gal)

**items I needed due to heavy presence of thread lock compound, I was forced to cut the lines and later destroy the brass extracting them from the case.

 

750 idle on an automatic is stock, 600 for a manual... at least for a 97. I don't know if they changed that on any other years.
When I did my cab and trans swap I ordered a canned tune from Hemifever with the trans delete. At 600 rpm I couldn't do anything at idle, it wouldn't even try to charge. Since we were having issues with the tune throwing a few un readable codes I had Sean bump the idle back up to 750 and it made a world of difference. When this 408 goes in I'm going to try to get my Idle at 800 for charging and pulling at idle through the hills.

 

I dunno either, ole girl is stock as all hell, 2000 5.9 auto. I doubt tow pack would make it idle as a stick......I just know what my dials are saying. Additionally She ain't got a single issue with bolting up to 5 mph if dropped in gear and let go on a flat stretch.