I have run into problems with my 1990 chrysler new yorker 5th avenue. the transmission will not shift out of low gear. the in-car read out simply states “check transmision” I was told that it might only be a transmission electronic controller problem and that the car is in some kind of ‘limp’ mode so as not to create anymore problems? Could this be true and when transmissions go out, do some gears work and others don’t. When I start to drive it runs until about 15 mph and then it is like the transmission disengages, the care reves, but it does not drive. i have not tried reverse. thanks.
Yes it sounds like the transmission computer has found a problem with either the input sensors or a hard problem with the transmission. However, from your description the transmission is not going into ‘limp home’ mode. Limp home locks the transmission in second – no shifts involved and you will have reverse. The slipping indicates that a clutch is not engaging so you may have a solenoid problem or an internal hard problem. Have a transmission technician scan the computer for codes and check the line pressure as the transmission shifts and slips. A little diagnosis will narrow your problem and maybe save you some bucks.
This 604 transmission is electronic. I would check for codes first. Also have the CVI values read. CVI’s are the clutch volume indexes which is basicly telling you how much fluid is required to fill that particular clutch. If my hunch is right, you probably will see high readings in the underdrive or the 2/4 clutch drum. What I think is happening is a broken snap ring on either one of these clutches is causing that clutch to come apart when the transmission directs fluid to it. Broken snap rings are very common in especially the underdrive clutch. I see this very often in the 604’s which cross my bench.
Oh, you are not in limp mode. Limp mode is when the computer finds a fault and commands the transmission into 3rd gear. It will stay in 3rd gear until the problem is fixed and the codes cleared.