1985 transmission issue
12-01-2013, 12:56 PM
#1
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1985 transmission issue
Hey guys, I have an issue with my '85 Automatic (700R4). it was shifting really hard and pretty early. I spoke with my tranny guy who said it sounded like the torque converter was locking up too early and then wouldn't release when it should have, it would release but not until it shifted down to first gear.
he suggested that I disconnect the wiring to the tranny and see how it did after that. I unplugged the connector and everything started working like it should except for no lock-up function.
he said it sounded like the lock-up solonoid was stuck which was causing the torque converter to lockup as soon as it hit second gear.
I took the car in to him to have the solonoid replaced and have the tranny serviced at the same time, he then called and said the the solonoid looked ok but the ECM was sending signals to lock-up when it shouldn't be. he temporarlily wired the lock-up so it comes on when the car goes into overdrive and comes off when the OD comes out.
I would rather have everything work like the factory designed it. has anyone had any issues with the ECM sending incorrect signals to the torque converter??
the car runs great and has no issues other than this one thing.
by the way, I REALLY trust this tranny guy, he has been building trannys forever and does a ton of work for our local drag guys, he is highly recommended.
he suggested that I disconnect the wiring to the tranny and see how it did after that. I unplugged the connector and everything started working like it should except for no lock-up function.
he said it sounded like the lock-up solonoid was stuck which was causing the torque converter to lockup as soon as it hit second gear.
I took the car in to him to have the solonoid replaced and have the tranny serviced at the same time, he then called and said the the solonoid looked ok but the ECM was sending signals to lock-up when it shouldn't be. he temporarlily wired the lock-up so it comes on when the car goes into overdrive and comes off when the OD comes out.
I would rather have everything work like the factory designed it. has anyone had any issues with the ECM sending incorrect signals to the torque converter??
the car runs great and has no issues other than this one thing.
by the way, I REALLY trust this tranny guy, he has been building trannys forever and does a ton of work for our local drag guys, he is highly recommended.
12-02-2013, 03:05 AM
#2
Race Director
The ECM uses vehicle speed to decide when to turn on the TCC. In my car it's 40 MPH. It doesn't matter what gear, it's still 40 MPH.
The VSS signal goes to the dash first and then to the ECM. Does your speedometer do anything weird?
Maybe there's an intermittent connection between the dash and the ECM. I suggest using contact cleaner on the cluster connectors and the ECM connectors. Interestingly, they are both the same type of connector.
The VSS signal goes to the dash first and then to the ECM. Does your speedometer do anything weird?
Maybe there's an intermittent connection between the dash and the ECM. I suggest using contact cleaner on the cluster connectors and the ECM connectors. Interestingly, they are both the same type of connector.