Still want to stick with the G but did not know whether to trade in for a newer model or keep this one. Have no desire to trade in for a newer model but did not know expected longevity of the 2003 with 150k miles. Needs two new door locks and the keeps say T/C shift incomplete so do not want to dump a bunch of $ into something that is nearing end of life.
Sounds like you might need 2 electronic door latches, and a possible transfer case motor(would be interested to see what you have for stored fault codes in the TCU). Last TC motor we replaced had this fault code; P2213 (2213) the sensor from component direction sensor is implausible.
Here's some info I had gathered off the forums for the TC display saying N vs H or L;
“Well, the TC control module only "knows" the position of the shaft by keeping count of pulses coming from a Hall effect sensor on the motor. If the splines are slipping, then that method doesn't work any more. The motor is spinning, sending pulses, but it's not moving anything. The module doesn't know about the slipping, it just knows the motor is spinning. So pretty quickly, the shift fork in the TC is not where the module thinks it is, leading to unpleasantness.
If you never shift from H to L, you might think this would not affect you. But it does. The reason is that every time you turn on the ignition and engage D, the TC module does a quick confirmation that it is in the right position by running the motor back and forth a little, touching briefly against what it thinks is the end of travel and coming back a bit from that. If the splines are failing, then it's not going to find the limit of travel where it was expecting it, and then it no longer knows where it is. So you get a blank square instead of H or L in the display. Or possibly a TC in Neutral message if it came up with a new incorrect position that is close to where N is.
This is a process that would lead to progressive failure of the splines. Each time they slip, they wear a little more, making them more likely to slip next time. Each time the control module loses track of the position, it runs the risk of ramming the motor against the limit and causes more spline damage. This is a very unvirtuous cycle between the motor and the control module.
Once the process really gets going, the servo motor is bound to fail. The splines will get stripped to the point that they can't work at all, and no amount of resetting or re-adapting will fix it. How long that takes probably depends on just how much torque your particular motor can make, how strong the splines are in that batch, etc. So some may go forever, and some start to fail right away. If you never strip that first tooth, the process never gets going.
I suspect that the problem was exacerbated by faulty control modules in 2002. If the control module was not functioning correctly, eg miscounting pulses, or forgetting it's position, then it makes it more likely it will drive the motor to the end limit, and start stripping splines.
At some point, Merc started improving these parts. My servo motor was made in July 2003 (replacement of the original 2002 motor) and it was still too weak. The control module was also upgraded several times. I suspect you need to have a good motor and a good module to eliminate the problem, but I don't know which versions/dates would be good. The latest versions of both would be a good place to start.”
HTH some.