Chrysler Repair: 1999 300M Trouble shifting, coolant levels, 1999 chrysler 300m

Question
QUESTION: I have a 1999 Chrysler 300M with 125k miles.  After driving for an hour and a half yesterday, I stopped to fill up on gas, and as I got back on the highway, I noticed that the speedometer had stopped registering at all.  Then, as I was accelerating up the ramp, the engine was revving higher than I typically hear it, and not shifting.  No matter the speed or RPM, no shift seemed to be taking place.  I tried putting the car in AutoStick mode, where it identifies as being in 2nd gear, but does not respond to inputs to change into 1st or 3rd.  If I decelerate rapidly, the vehicle stalls just before stopping.  Upon turning the car off, then starting up again, the AutoStick registers as being in 1st, and during acceleration, there is a noticeable shudder where it moves to 2nd.  The stall doesn't happen every time, and when it doesn't, the car seems to stay in 2nd, regardless of being stopped or turned off.  My oil, transmission fluid, and coolant levels are normal, and other gauges (fuel, tach, temp) appear to be fine.  Shortly after this began, the "Check Engine" light appeared, and when the car stalls (since this started yesterday, has happened 5 times, during 1/5-1/6 of all stops) the Oil Pressure light flashes on, but goes away upon restart.  I had a garage run the diagnostic computer against it today, which informed them that the transmission needs replacing/rebuilding.  Before committing to that level of work, I wanted to see if there were any other possibilities that result in similar symptoms, and if so, how I could differentiate, or potentially attempt to fix and find out.

http://en.allexperts.com/q/Chrysler-Repair-807/1999-300M-1st-gear.htm brought me here, but seemed dissimilar enough to my situation to warrant a new question.

ANSWER: Hi Geoff,
The fact that the speedo went out when this all began leads me to suggest that you need to get the specific fault code numbers that they read out as that failure of the speedo tells me that the digital data communication system was not providing information from the transmission output speed sensor to the powertrain controller to body computer to speedometer. This might be the main cause of your problem rather than some sort of internal damage to the transmission. There are a wide variety of 4-digit fault codes and you need to know exactly which one(s) are there. If necessary get another readout at an Autozone parts store (free) or another independent shop. But ask the numbers, what they believe they mean, what are the possible repairs, and how much. Then write back and we can compare that to the shop manual information.
Roland


PS For example it may be a simple failure of the output speed sensor which gives the info for the speedo reading AND for shifting. That is a simple replacement. Your trans is now simply in "limp-in mode" which is a self-protective stance that it assumes to avoid damage. So get the numbers is the bottom line.

---------- FOLLOW-UP ----------

QUESTION: The readout from the shop is (came on my bill):
"P0700, P0731, P1790 (NEEDS TRANSMISSION)"

When I do the self-diagnostic On-Off-On-Off-On, I get "P1684", "-----", "P0700", "------", "dONe".  I imagine the P1684 is a result of something the shop was doing today (Battery disconnect within last 50 starts, based on my research).

This shop doesn't do transmission work, so they were not very detailed as to what they thought the problem was, or what the options for fixing it were.  Primarily, they were directing me to any shop I could find that does transmission work to get further information.

Answer
Hi Geoff,
There are some mechanical tests that can be done on the trans to access whether it is or is not a rebuild issue. My inclination would be to look for some good references about trans shops that know the Chrysler electronic trans axle. It may be an internal clutch wear out situation, or it could be a solenoid switch issue which is reparable without removing/dismantling the transmission, and I still suspect that the loss of speedo (although there should be a fault if the output speed sensor has gone bad) is very relevant to the problem being electronics. Be sure to point out the loss of speedo when you go for further evaluation.
So that is about all that can be said. Let me know, please, what you learn from a well-recommended independent trans shop. It definitely is not conclusive that the only explanation is an internal problem.
The 700 is not relevant becuase there are the other codes. The 731 says there is a fault in the speed ratio (but that requires a working output speed sensor) and the 1790 says the problem is detected shortly after a shift. You are correct about the 1684, not related and not important.
Roland