Chrysler Repair: Transmission problem with 1995 3.0//6

Question
I started having problem with my car advancing to 3rd gear when driving, also when in park position when I put into reverse and drive my engine bangs into these gears, I replaced the transmission control module(TCM) I read this could be the problem. But as I've been researching more and more I'm determined that in could either be the input or output speed sensors. I know the best way to diagnose is to take it in and have the computer give me codes, that's my next step, I'm sure I'll get answers but maybe mislead advise. I refuse to believe that I need to replace the transmission as many have said. My car has a strong transmission and replacing it would b costly and isn't the answer. This being my gut feeling. Can you help with my problem could it be the sensors?

Answer
Hi Virginia,
Do you mean it delays in shifting to 3rd gear or that it will only drive up to 2nd gear and no further? The latter would be called "limp-in mode" which the trans controller will do in order to protect against unnecessary damage until you can find out what is wrong. It does that by blocking the transmission relay from energizing the shifting functions.
Harsh engagement into reverse from park can be due to too high an idle speed, too high hydraulic pressure, of a valve body malfunction as the simpler things and don't involve removal and rebuilding, but there can be internal damage that also causes harsh engagement that which would require a rebuild.
Start by checking the fluid level on the transmission dipstick. If that is alright then
I would get the fault code readout using the blue diagnostic connector under the dash using an OBD-I reader made by Snap-on or Chrysler. Make sure the blue plug is used under the dash, not the connector in the engine compartment. Let me know the 2-digit fault codes and we'll go from there. I doubt the issue is either speed sensor but the fault codes may give us a clue.
Roland