Mitsubishi Repair: Mitsubishi RVR, 1996, mitsubishi rvr, limp home

Question
I've been having auto transmission problems, replaced several gearboxes but two problems still persist. 1. Delay in transmission change gear 2 to 3. and 2. No Overdrive Gear. The diagnostics analysis indicates "gear 4 not synchronised" (code 54). Would you know what this code implies in the RVR a/t gearbox and how to "synchronise" gear 4? Please guide me, thanks!

Answer
Charles: You need to find a book on the codes, I shall look around and see what I can find. But either that is a speed sensor, input or output sensor, differetial speed sensor or something else. Your car has a safety thing, well if the computer is picking up a problem in the system. It will stop the transmission from shifting into any other gear but 3. That way you could get the car home but just not drive to fast and so messing up parts of the transmission. Such if the signals from the transmission, engine and wheels get out of sync or confused, you get third gear limp home mode. Have you tried to change the fluid, filter and then put in a bit of conditioner? Have you check the fluid is it brown or black in color and smells burnt? If it is pink and brown then the fluid needs to be changed, but then you should change that once a year if you do a lot of city driving.  But it sounds like a bad sensor. You need to buy a repair manual for your car, it will explain where those sensors go and how to change them. There are also code books as to explain what sensor that is. But I will try to look that up later to day and write you back. You know that the computer controls how the transmission shifts. I have heard from so many people that have just went out and changed the transmission only to still have the same problem because it was a sensor and not the transmission. Let me check on that code and see what I can find. I hope this helps and good luck! Linda