Questionmy car all of asudden stop switching gears, feels like its in 2nd gear, now we also had a problem with the speedometer jumping around when it got real hot out or sat for awhile after a few minutes it starts to work, but the trans wont jump into gear. when i back out of the driveway and put it into drive its ok but 2 seconds and wham it slams into 2nd gear, when i shut the car off and turn it on it slams into L1 and then back into 2nd but thats it. what can i do? does it sound like a bad sensor? is there a sensor at the end of the trans to be replaced or cleaned?
AnswerHi Russell,
Yes there is an output shaft speed sensor that is located just to the left (or driver's side) of the base of the vertical gear shifter shaft to which the shifter cable is attached and which is all located on the side of the trans that faces the front of the car. That output shaft sensor could be bad and cause the failure to shift out of 2nd gear. It also drives the speedometer so that might explain why the speedo is flakey. But rather than simply investing in the sensor (I think it costs a little under $100, and you could replace it yourself) it is propbably wiser to do a "readout of the transmission computer" which is an electronic test for the presence of coded numbers representing different faults that the transmission is experiencing at the time when it locks up into 2nd gear. That exact lock up is what happens when the transmission computer notices something is wrong and so it protects the transmission by only driving in 2nd gear until it can be serviced so as to protect against any further damage. It is called "limp-in mode".
The chances are there is some internal mechanical wear/damage to the internal clutches of the transmission, but because the cost of rebuilding is so high it is worth spending a little on analyzing whether that is true or not. It may also be the case that the problem is with the sensor/electrical connections/computer or with the transmission fluid system (hydraulic) and those can be repaired without removing or rebuilding the transmission at much less cost.
The transmission has an electronic controller that has the ability to recognize malfunctions and store them in its memory as two-digit fault codes. An electronic readout device is plugged into a port under the dash to access the memory and tell you the fault code numbers. It would be worth spending about $50 to have this done just in case the problem had to do with the hydraulic or electronic parts rather than the internal mechanical parts because those could be repaired without taking the trans out of the car and dismantling it. So a dealer or a competent independent transmission shop (but NOT a franchise type like Aamco where the usual answer will be to do a "rebuild") with a reader for Chrysler transmissions should be able to do that. Ask for the code number(s), what they mean, what repair is needed and how much it will cost. Be sure that they have the 6-pin ("bus diagnostic connector") reader plug adapter that will give them access to the memory via the blue plug-port under the dash. This is NOT the same plug as is in the engine compartment (which is a black 5-wire/6-pin plug) for accessing the engine controller memory. Their reader also has to be equiped with a program (cartridge) that accesses the transmission computer. A Chrysler dealer will have this device called a DRB II.
Then write back and we'll evaluate what you were told, particularly what are the fault code numbers. I have the '94 factory repair manual and can look up what the numbers mean and what needs to be done to fix this.
You don't have to authorize a repair until you decide you understand the situation, and maybe get another repair estimate. You might even ask before they do the readout if in the case you decide to authorize the shop to do the repair "will the cost of the readout be credited against the cost of the repair"?
So take your time with this so you don't do any more unnecessary repairs. The cost of a rebuild is high so getting a second bid is worthwhile and also comparing warranty provisions is wise.
But that readout is the only way to avoid doing the wrong repair. I doubt the sensor is cleanable or repairable, but if you get a 57 code only that would indicate the sensor is the cause of the problem.
Roland
