The transmission appears to be stuck in "limp-in"

Yes, that is the whole idea of Limp Mode. It limits you to first and second gear so you can limp slowly to the nearest garage without causing catastrophic damage to the engine. What you need to do is connect a good quality DTC code reader scan tool and see the real reason that Limp Mode has been engaged.

https://www.google.com/search?q=1999+jeep+cherokee+limp+mode+causes

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Your transmission is stuck in the so called limp mode to protect the transmission against further damage, take the car to a repair shop or dealer for further testing

Your transmission is stuck in so called limp mode to protect the transmission against further damage.....take the car to a shop or dealer to get it tested.

P0455 = Evap leak monitor large leak detected.
This code usually means the gas cap may have been loose or needs the rubber gasket.

P0500 = No vehicle speed sensor signal.
Vehicle speed sensor is located on the transmission near one of the axle shafts (it may need replacing).

P0700 = EATX controller DTC present.
This simply means you have transmission related codes.

P0732 = Gear ratio error in 2nd gear.
This code is of some concern, it means the transmission is slipping in 2nd gear. However the trans may be in limp mode due to the speed sensor code (limp mode means the trans starts out in second gear in order to at least get to a mechanic). The first thing I would do is have these codes cleared as there may be absolutely nothing wrong with the transmission (especially if you pull the trans dip stick and the fluid does not have a burnt smell. The vehicle should drive normally after that. If the check engine light comes back, have the codes scanned ASAP (before any other unrelated code sets). Chances are it may be the output speed sensor if this happens (easy fix). Hope this helps

Regards

this sounds like transmission failure as limp mode would allow reverse and 2nd gear only to allow you to drive to a shop to have it checked out.

Sounds like your transmission is in limp mode. This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

The other from what you described, trans shifts 2nd to 3rd by itself in D or OD and locks the converter : ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

Thank you for using fixya and have your Safari scanned for the DTC codes that would indicate what issues your transmission is having to put you in to limp mode.

The town and country vans are know for transmission problems and it would not be stuck in 2nd gear if it was in limp mode. Limp mode typically controls the engine. I have seen people do a transmission flush/filter and add lucas to temporary fix the problem. There is also a good chance that the transmission has a solenoid problem preventing it from shifting into any other gears but second. Hope this helps!

Most transmissions have a limp mode, or limp-home mode.
If the driveline computer thinks there is something wrong, it can lock the transmission into one gear, such as 2nd gear. Usually reverse will also be available. The Impala automatic has 4 speeds. 2nd speed or gear will get you home, but the engine rpms can get a little high. I wouldn't get on the expressway will in limp mode.
Before taking to the shop, you might want to try and reset limp mode by turning the car off for a couple minutes, or you may have to disconnect and reconnect the battery.

most newer vehicles  have transmission control modules,that go to a default of 2nd or 3rd gear when they go bad!  I had a 91 plymouth stuck in 3rd gear because of this module! could be your problem!    when mine went out, it smelled like something electrical burned inside the the passenger cabin! I would check all the electrical connections on the transmission first    good luck