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I have a 97 Cutlass Supreme with 142k miles on it - 3.1/4T60E. I bought it with some known transmission issues.
When I bought it, the tranny was in limp mode. I managed to clear that, only to find that in order to shift from 1-2 you had to goose the power, then take your foot off the gas, then get back into it. Once it shifted 1-2, the 2-3 shift was fine, but it would not go into overdrive.
I replaced the 1-2 shift solenoid without taking the transmission out of the car (which was very hard on my patience and my fingers) and that fixed the 1-2 shift problem. Then I discovered a shudder following the 1-2 shift.
I replaced the vacuum modulator on the front of the transmission because when I removed the old one, the plunger moved with no resistance. That fixed the shudder on the 1-2 shift.
So now, I'm down to a 4T60E that won't go into overdrive. Here are the symptoms:
1) With the shift selector in OD, the car shifts up to D just fine and will lock up the torque converter, but when you take your foot off the gas, the engine will drop to idle and the car is essentially coasting.
2) With the shift selector in D(3), the car shifts to D fine and the torque converter locks up, but the transmission stays engaged and you can engine brake like you would expect to be able to in D (3)
Here is what I have checked / tested so far:
1) no codes in the PCM
2) speed sensor reports proper speed (as read by Actron scan tool)
3) brake pedal switches both operate properly and are installed properly
4) changed trans fluid and filter (while changing 1-2 solenoid)
5) 18lb of vacuum to the vac modulator
6) Load% and MAF volumes seem to be ok based on scan tool
7) pulled transmission selector witch (NSS) and tried to clean it, but it's riveted shut
car starts only in P and N like it should, reverse lights come on with selector in R
I would really like to hope it's the transmission selector switch, but I'm not terribly optimistic that's it based on the car starting in the gears it's supposed to and the reverse lights working. Does anyone know how to test the selector switch? I hate to just throw parts at it without being able to verify they are bad. Is it possible for only the OD position in the switch to go bad?
Any other inputs would be great. I'm hoping it's not going to require a rebuild, but the more I troubleshoot the problem, the more I suspect it might. I have sourced a used 4T60E near me for $40 that has about 70k miles on it, but I'm not sure I have the time or tools to swap out the transmission myself.
Thanks!
Ryan
When I bought it, the tranny was in limp mode. I managed to clear that, only to find that in order to shift from 1-2 you had to goose the power, then take your foot off the gas, then get back into it. Once it shifted 1-2, the 2-3 shift was fine, but it would not go into overdrive.
I replaced the 1-2 shift solenoid without taking the transmission out of the car (which was very hard on my patience and my fingers) and that fixed the 1-2 shift problem. Then I discovered a shudder following the 1-2 shift.
I replaced the vacuum modulator on the front of the transmission because when I removed the old one, the plunger moved with no resistance. That fixed the shudder on the 1-2 shift.
So now, I'm down to a 4T60E that won't go into overdrive. Here are the symptoms:
1) With the shift selector in OD, the car shifts up to D just fine and will lock up the torque converter, but when you take your foot off the gas, the engine will drop to idle and the car is essentially coasting.
2) With the shift selector in D(3), the car shifts to D fine and the torque converter locks up, but the transmission stays engaged and you can engine brake like you would expect to be able to in D (3)
Here is what I have checked / tested so far:
1) no codes in the PCM
2) speed sensor reports proper speed (as read by Actron scan tool)
3) brake pedal switches both operate properly and are installed properly
4) changed trans fluid and filter (while changing 1-2 solenoid)
5) 18lb of vacuum to the vac modulator
6) Load% and MAF volumes seem to be ok based on scan tool
7) pulled transmission selector witch (NSS) and tried to clean it, but it's riveted shut
car starts only in P and N like it should, reverse lights come on with selector in RI would really like to hope it's the transmission selector switch, but I'm not terribly optimistic that's it based on the car starting in the gears it's supposed to and the reverse lights working. Does anyone know how to test the selector switch? I hate to just throw parts at it without being able to verify they are bad. Is it possible for only the OD position in the switch to go bad?
Any other inputs would be great. I'm hoping it's not going to require a rebuild, but the more I troubleshoot the problem, the more I suspect it might. I have sourced a used 4T60E near me for $40 that has about 70k miles on it, but I'm not sure I have the time or tools to swap out the transmission myself.
Thanks!
Ryan
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