I have 1997 Jeep Grand Cherokee V8 limited. There are different 4WD modes available. I was wondering which 4WD mode is the most fuel efficient and how do you engage the different 4WD modes?

nice pictures in the linky

https://www.google.com/search?q=1997+jeep+grand+cherokee+limited+5.2+v8+transmission&safe=off&rlz=1C1QJDB_enCA643CA644&sxsrf=ALeKk02B4cUCDshUkXE02HmZ9FArC-2O7Q:1619326858701&source=lnms&tbm=isch&sa=X&ved=2ahUKEwilgMDRzpjwAhXUZc0KHdrFDZMQ_AUoAnoECAEQBA&biw=1920&bih=937

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No sir they will not interchange. i worked at a transmission shop for 7 years. the inline 6 has a 500 trans in it and the v8 has a 518 trans in it. the bellhousings are different.

sometimes because of non moving part inside of transfer case, elements stuck or gets slower to react against changes in mode. try to switch to another transfer mode in nuetral position and stopping. after switching to desired mode move few hundred meters.

if this does not help you may need to check linkage on transfer case.

The ZJ models, manufactured from 1993 to 1998, originally came in three general trims, the Base, Laredo, and the Limited. I have the same '93 ZJ Limited 5.2L V8, nice engine!!!

Just one in the Internet: Jeep-ZJ-Grand-Cherokee-Manual-de-Usuario (spanish)

Also, its possible that you are interesting in the Repair Manual, just tell me.

Keep in touch.

Estoy asumiendo que es GRAND CHEROKEE, sin embargo en la descripcion indicas Cherokee, asi que puedo decirte lo siguiente para....
Make: JEEP
Model: GRAND CHEROKEE - LIMITED
Year: 1997
Engine: V8 - 5.2L - FI - - GAS

IRIDIUM PLUG Part Number 9203 .040" GAP

Otros detalles los encuentras en CHAMPION.

Saludos (recuerda calificar esta ayuda)

Not sure what you mean by "4wd all the time, Neutral".
But I can tell you how it's supposed to operate.

The three modes are 2wd, 4wd high and 4wd low. When switching between 2wd and 4wd high it makes no difference whether the Jeep is moving or in neutral. The only condition that needs to be obseved when switching from 2 to 4 high is the speed of the Jeep. It should not be done above 45mph.
The switch from 4wd high to 4wd low is a different animal. The Jeep must be stopped and in neutral. Also you should be aware that it is not a pleasant sound or feel when moving from high to low so you should worry to much about the lowed junking sound.
At times it may even be necessary to put the lever back to the high position and move the Jeep a couple feet to align gears before it goes into low.

This is the reason for the relative ease when switching from 2wd to 4wd high.
There is an art to switching from 2wd to 4wd high then to 4wd low. Once your son becomes familiar with the Jeep and begins using the different modes it will become easier.
I would like to add one more piece of advice. After building Jeeps for over 25 years and owning several I have found that 8 out of 10 times that 4wd low is used, it's used incorrectly or not needed at all. It's a good idea to find someone who has experience with 4wd to give a bit of instruction on how it should be used. Especially in the mountains.
Let me know if you need any clarification on anything.
I hope this helps.

The 46rh is a hydraulic transmission as where the 46re is an electric transmission. With minor wiring you can replace the 46re with the 46rh but not the other way around. Your transmission would stay in limp mode and wouldn't shift out of 2nd gear. So the answer is no.

If you have the V8 engine, the filter is actually part of the fuel pump. WHICH IS IN THE TANK

If you have the V8 engine, it is actually part of the fuel pump, which is IN the tank

fuel filter is clogged try replacing it