Expert: Roland Finston - 5/8/2005

Question
I was driving home from work and went around a corner and heard a ratcheting noise and then did not have drive mode !It will not shift from second to drive! It has 152,000 miles on it but was shifting perfect,no signs of slipping or any unusal noises! What do you think might be the problem ? Are there any checks that I can make?
Automatic trans. V6 engine

Answer
Hi Larry,
The ratcheting sound when going around a corner is more often associated with a CV joint on the outer end of either drive shaft having lost its grease because of a torn rubber boot. But the concurrence of that with the refusal of the trans to shift makes me wonder if the noise had to do with the trans instead. You could look under the car at the the drive shafts and see how the boots at both ends appear to you. They should have no tears and no signs of leaking grease. The CV's will usually only make such a noise when the grease has spun out and it begins to complain when the wheels are in the turning mode rather than going straight down the road, but later they will progress to making the noise even then. If you get to it before too much frictional wear has occured you can refill the joint and put on a new boot if you do it yourself, but most garages will generally sell you on replacing the joint or the entire half shaft which of course is more expensive part-wise but the same labor cost-wise. If the CV's are alright then the issue is clearly only the transmission:
It sounds like your electronically controlled transaxle has detected some problem with the unit and in order to avoid any unnecessary damage has gone into "limp-in" mode which means it won't shift out of 2nd gear. It allows the car to be driven at moderate speed to a garage for analysis. The transmission controller logs the problem as a two digit number stored in its memory. The transmission controller does not have a self-read capability as does the engine controller so you can't use the ignition switch to get the codes.
The dealer or a competent transmission shop should have a readout unit to find out what the code number is and from that they can make some conclusions about whether the trans can be repaired without being removed from the car (for example a electrical or hydraulic pressure problem) OR if some mechanical damage is involved (but follow-up a "mechanical damage" diagnosis by dropping the oil pans and looking for debris to be present or not) which if true would require a pretty expensive rebuild, I am sorry to say. No debris in the pans would suggest the possibility of an hydraulic problem only.
So that is my best advice: go to a dealer/independent and ask for a diagnostic readout of the transmission controller and an estimate for repairs. Get the code number(s), and if you like, write back with a 'follow-up' question to me and we can compare what you are told with what the shop manual says is the problem of that code, and then decide if you are getting the correct advice. You don't have to give them a blank check, just ask for a diagnostic readout, the code numbers and the repair estimate. It will cost something to get that done (should be under $100), but the more information you have before going forward the better. I would not go to a franchise-type (AAMCO) transmission shop, but rather an independent with a good reputation or a Chrysler dealer. The place has to have a code reader with the adapter plug that mates with the Chrysler-type transmission readout plug. So inquire whether that is true, if you don't go to a dealer shop. If you go ahead with the repair, the cost of the diagnosis is often credited against the repair cost. But don't rush to judgement because a total rebuild costs about $1,500 so you don't want to authorize that unless it is the only possibility. Let me know what happens, because the feedback helps me too.
Roland