So I have a 98 24v, 4x4 47re and it has no overdrive. Fluid is good, trans was rebuilt at some point.
Here's what I've done, I've started by checking ohm on od and lu solenoids and that was good (33ohms each)
Then I back probed the plug and went for a drive, at the point of overdrive command it dropped the 12 volts as it should, (but did not go into overdrive) and then shortly after, lock up dropped volts and convertor locked up as it should.
Then I went back to the shop and hooked up a pressure gauge to the overdrive port and went for a ride, 12 volt power dropped and the pressure gauge layed on zero. I was expecting to see the gauge jump up, meaning a big leak. But the gauge layed on 0, so I dropped the pan and pulled od and lu solenoids and bench ohmd them, still good, I put air into the port on the solenoid and air flows freely through the solenoid, when I apply 12v the valve closes as it should. So now that's where I'm at, where should I go next? I'm assuming it's something valve body related, maybe 3-4 shift valve or something, is that common to hang? I've done lots of reading but it's the usual "no overdrive" with a response of "put a mystery switch in, if it works its electrical, if it don't work, it's the solenoid", which we know isn't true lol there's a lot of other things involved besides a solenoid, although that is a common failure. Thanks in advance!
Here's what I've done, I've started by checking ohm on od and lu solenoids and that was good (33ohms each)
Then I back probed the plug and went for a drive, at the point of overdrive command it dropped the 12 volts as it should, (but did not go into overdrive) and then shortly after, lock up dropped volts and convertor locked up as it should.
Then I went back to the shop and hooked up a pressure gauge to the overdrive port and went for a ride, 12 volt power dropped and the pressure gauge layed on zero. I was expecting to see the gauge jump up, meaning a big leak. But the gauge layed on 0, so I dropped the pan and pulled od and lu solenoids and bench ohmd them, still good, I put air into the port on the solenoid and air flows freely through the solenoid, when I apply 12v the valve closes as it should. So now that's where I'm at, where should I go next? I'm assuming it's something valve body related, maybe 3-4 shift valve or something, is that common to hang? I've done lots of reading but it's the usual "no overdrive" with a response of "put a mystery switch in, if it works its electrical, if it don't work, it's the solenoid", which we know isn't true lol there's a lot of other things involved besides a solenoid, although that is a common failure. Thanks in advance!