transmission replacement on 03 awd/4wd
 

the transmission of my 03 sport with 120k is in it last days.
In the mornings or late at night I need to warm up the engine for 5 - 10 minutes before it can engage in to D.
Last week trying to past in a up hill a really slow 18 Wheller the transmission lock it self (like stepping in brake really hard) got off the gas pedal, hit the gas again and lock again this happens 3 times so a pull over and let it cool down, although my engine is overheating (3/4 on the thermometer) no a/t light was on.
Now every time I am going up in hill the transmission hesitate, and if I am going to a complete stop I have to put it in N or the engine dies.
MY question is the next.
To replace the transmission I have to look for a exactly the same type ADW/4WD or the 2WD work (assuming the difference is the transfer that is attach to the transmission)?
I live in Honduras Central America and a new transmission cost like haft the price of my montero, so my option are on used parts.

Your description make me think your problem is the torque converter. Have you done any maintenance to your transmission since you purchased your truck?

I bought the Montero 2 year ago with 90k, in that time a I've make 3 oil changes to the transmission.
The torque converter is that round thing (looks like a turbine) inside the transmission case ?
Do you think I should try just replacing it, any montero transmission could be the donor?

Is there any VIN Number for my transmission, or part number I'm considering a overhaul kit.

ok, my transmission is out of the car and I'm waiting for the replacement to come on next Tuesday.
There is a lick in the transfer from a sensor, my question are :
1- Do I need to replace the sensor or just re install it with new silicone?
2- What the correct oil to replace in the transfer and differential ?

Yes, that is the torque converter.

1 - I would replace, since it's not every day this is going to be removed.

2 - GL-4 75W-90, 80W-90 or SAE 90 for the transfer case. GL-5 75W-90 or 80W-90 for the differential.

Now What?
 

I just bought a used transmission, during the test drive my montero stay in 2nd gear, the "N" started blinking in the dashboard, we scan the computer and pick up the PO 731 code (something in first and second gear inappropriate relation).
Is this a electrical problem or a mechanical problem?
It's something in the transmission or in the car that I should look for.
Need my car back (over a month in taxis)