Re: Ultramatic - stuck in park
Posted by HH56 On 2023/7/29 16:26:50
First question is how much grade is an "almost level driveway"? If the driveway has a decided slant it could be the incline has put a lot of load on the park gear and the motor does not have the power to pull the pawl out of mesh with the park gear. This happens more than you want to think about. Another all too common issue is running the front tire into a curb so a lot of pressure is on the tire. That pressure pushes back and again puts strain on the park gear. Funny story is that not coming out of park when the car was new is the reason my car became a used car very early in its life.
If too much grade is the reason, only cure is to somehow get the pressure off the park gear. Blocking one rear wheel and raising the other wheel will do it or using another car or maybe a few helpers to push opposite the grade is another. Once pressure is off put the trans in neutral and use the emergency brake.
If grade is not the issue, electrically, there could be several things. The easiest to check is to make sure the plastic plug under the dash is well seated and that none of the terminals have pushed out of either side of the plug resulting in a bad connection.
Second thing is if the auto park relay is still in the car make sure the relay has not failed and trans is electrically being commanded to stay in park. You can quickly remove the auto park function by disconnecting the green wire running between the circuit breaker and end terminal on auto park relay. It is an always hot wire so disconnect the battery or be very careful disconnecting and handling it. If you can shift into another gear with it disconnected then you will know something is wrong in the autopark circuit. Disconnecting only the green wire is a quick and dirty trick so without more work, the park button will not be usable again until the cause is found and fixed.
If the auto park relay has been bypassed or removed from the car then it is sounding like a more serious issue. If none of those suggestions work to get the car able to move I am afraid you will need to do some serious troubleshooting, some of which might involve getting under the car and possibly removing the actuator assy which is not an easy or fun job. If the actuator over travelled and a finger lost contact with the contact segment and segment cannot be manually driven back electrically, there is no access to be able to fix that problem with the actuator still attached to the transmission .
Here is the Autolite drawing showing the complete stock wiring circuit minus the control relay. Hard to guess what might have been changed on your car but the control relay was discontinued fairly early in production. It is shown as being present in all the factory wiring diagrams. There was a bulletin suggesting dealers remove it but still might be on some cars.
Attach file:
PB autopark 2.jpg (171.71 KB)
If too much grade is the reason, only cure is to somehow get the pressure off the park gear. Blocking one rear wheel and raising the other wheel will do it or using another car or maybe a few helpers to push opposite the grade is another. Once pressure is off put the trans in neutral and use the emergency brake.
If grade is not the issue, electrically, there could be several things. The easiest to check is to make sure the plastic plug under the dash is well seated and that none of the terminals have pushed out of either side of the plug resulting in a bad connection.
Second thing is if the auto park relay is still in the car make sure the relay has not failed and trans is electrically being commanded to stay in park. You can quickly remove the auto park function by disconnecting the green wire running between the circuit breaker and end terminal on auto park relay. It is an always hot wire so disconnect the battery or be very careful disconnecting and handling it. If you can shift into another gear with it disconnected then you will know something is wrong in the autopark circuit. Disconnecting only the green wire is a quick and dirty trick so without more work, the park button will not be usable again until the cause is found and fixed.
If the auto park relay has been bypassed or removed from the car then it is sounding like a more serious issue. If none of those suggestions work to get the car able to move I am afraid you will need to do some serious troubleshooting, some of which might involve getting under the car and possibly removing the actuator assy which is not an easy or fun job. If the actuator over travelled and a finger lost contact with the contact segment and segment cannot be manually driven back electrically, there is no access to be able to fix that problem with the actuator still attached to the transmission .
Here is the Autolite drawing showing the complete stock wiring circuit minus the control relay. Hard to guess what might have been changed on your car but the control relay was discontinued fairly early in production. It is shown as being present in all the factory wiring diagrams. There was a bulletin suggesting dealers remove it but still might be on some cars.
Attach file:
PB autopark 2.jpg (171.71 KB)
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