Shifting problems with 4L60E
Shifting problems with 4L60E I've got an issue with my trans. Car is a 2002 trans am with a 4l60e. Trans was rebuilt last year and had 5000 miles on it when I developed an issue where I lost 3 and 4 and no overdrive. I can shift manually 1 and 2 but nothing when I put it in D. It won't move at all. I disconnected the trans and had 3 gear or so I thought. I checked the tranny and realized a shift solenoid went bad. In addition I sent the trans back to be rebuilt and if they rebuilt it like they said they did with changing out all the components then the trans should be fine. I got it back and it was doin the same thing, no 3 and 4. When I manually shift to 3 it flares out and feels like it's in neutral. Thinking that the people went bad I sent out for a new one.
Today at I drove the car around town and I had the trans plugged in so I only had 1 and 2. Coming to a light I stopped and when I resumed it took forever for 1 to engage. Engine revved to 3500 before it shifted. 2 took a while to shift as well. Is this computer related and is it possible the new pcm will resolve it? Or does this sound mechanical? I am lost and I have no idea what else it could be.
Today at I drove the car around town and I had the trans plugged in so I only had 1 and 2. Coming to a light I stopped and when I resumed it took forever for 1 to engage. Engine revved to 3500 before it shifted. 2 took a while to shift as well. Is this computer related and is it possible the new pcm will resolve it? Or does this sound mechanical? I am lost and I have no idea what else it could be.
Last edited by mrvedit; Aug 31, 2016 at 09:35 AM. Reason: Moved from an old thread to its own thread
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First step with any trans problem is to scan for codes, even engine codes.
For example, if the PCM reads the TPS at e.g. 75% throttle, shifts will be very late.
Next step with any trans shifting problem is to connect a scanner to it which can command any gear. And read things like the TPS position. If you don't have and can't get one, take it to a trans shop. Perhaps some of the rentable scanner at auto stores can do this, but I don't know which ones. (If you know, please post.)
The other big diagnostic tool is a trans pressure gauge. The model ATD-5550 works perfectly and is under $35 on Amazon.
I will add that it is surprising how many trans "problems" are due to low fluid level (which needs to be checked carefully with the engine running) or clogged filter. Heck, I just learned recently that a high mileage trans could completely stop working because the filter got clogged with friction material. Sure the trans was well worn, but replacing the filter probably gave the owner another 10,000+ miles of life.
So those are the basic diagnostic steps for any trans problem.
I don't immediately see what your problem is, and I am a bit confused by how many trans replacements were done, especially since each one seemed to have different problems. Out of the many problem threads here, perhaps 2% were due to a bad PCM. So while rare, it is possible, especially if two transmissions have the same problem. Of course a bad engine sensor or bad tune could be the culprit too.
I hope that helps point you in the right direction.
For example, if the PCM reads the TPS at e.g. 75% throttle, shifts will be very late.
Next step with any trans shifting problem is to connect a scanner to it which can command any gear. And read things like the TPS position. If you don't have and can't get one, take it to a trans shop. Perhaps some of the rentable scanner at auto stores can do this, but I don't know which ones. (If you know, please post.)
The other big diagnostic tool is a trans pressure gauge. The model ATD-5550 works perfectly and is under $35 on Amazon.
I will add that it is surprising how many trans "problems" are due to low fluid level (which needs to be checked carefully with the engine running) or clogged filter. Heck, I just learned recently that a high mileage trans could completely stop working because the filter got clogged with friction material. Sure the trans was well worn, but replacing the filter probably gave the owner another 10,000+ miles of life.
So those are the basic diagnostic steps for any trans problem.
I don't immediately see what your problem is, and I am a bit confused by how many trans replacements were done, especially since each one seemed to have different problems. Out of the many problem threads here, perhaps 2% were due to a bad PCM. So while rare, it is possible, especially if two transmissions have the same problem. Of course a bad engine sensor or bad tune could be the culprit too.
I hope that helps point you in the right direction.
Yeah I guess one of the mistakes I made is writing that long post on my phone. To clarify, I developed an issue where I lost 3 and 4 recently. Nothing happened in D, no shifting at all. Has to be manually shifted.
So so it was then that I sent it out. When I recieved it it seemed to try to normally shift until it got to 3, then at that point, it seemed like it didn't engage all the way and flared out like in neutral. I had to manually shift it from then on. On a hunch I disconnected the trans electrical connector and started in D. The car moved. I then put it in 1 and the car started in 2 which is apparently normal. I put it in 3 and it feels like it's not engaging the gear fully. I get intermittent third gear essentially, or so it seems. I then checked resistance and found that the 2-3 shift solenoid was open. I replaced it. Thinking it might fix the issue, I plugged the trans back in and tried driving and it was fine in D til it got to 3rd. Then it flared out and would not move from a stop til I placed it in 1 manually and then 2. I have no manual 3rd or 4th.
I drove it again and this time it had a hard time engaging 1 manually and 2. It was a delayed lock in the gear. Car revved to 3500 before it shifted. Fluid level is good. Only thing I can think of is maf. The only code I have is for the shift solenoid 2-3 stuck open. It is not a hard code either, it comes and goes.
the only abnormality I found is that the blue pcm connector had some corrosion on the pins, cleaning it didn't help. Although it fixed an issue with my fans where number 1 speed would somehow turn on five seconds after the key was turned off and would stay on til I turned the key on again. Almost like a short to ground. I backprobed the pcm and found it to be the culprit. The wiring was good.
So so it was then that I sent it out. When I recieved it it seemed to try to normally shift until it got to 3, then at that point, it seemed like it didn't engage all the way and flared out like in neutral. I had to manually shift it from then on. On a hunch I disconnected the trans electrical connector and started in D. The car moved. I then put it in 1 and the car started in 2 which is apparently normal. I put it in 3 and it feels like it's not engaging the gear fully. I get intermittent third gear essentially, or so it seems. I then checked resistance and found that the 2-3 shift solenoid was open. I replaced it. Thinking it might fix the issue, I plugged the trans back in and tried driving and it was fine in D til it got to 3rd. Then it flared out and would not move from a stop til I placed it in 1 manually and then 2. I have no manual 3rd or 4th.
I drove it again and this time it had a hard time engaging 1 manually and 2. It was a delayed lock in the gear. Car revved to 3500 before it shifted. Fluid level is good. Only thing I can think of is maf. The only code I have is for the shift solenoid 2-3 stuck open. It is not a hard code either, it comes and goes.
the only abnormality I found is that the blue pcm connector had some corrosion on the pins, cleaning it didn't help. Although it fixed an issue with my fans where number 1 speed would somehow turn on five seconds after the key was turned off and would stay on til I turned the key on again. Almost like a short to ground. I backprobed the pcm and found it to be the culprit. The wiring was good.
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This would not be the first time a newly rebuilt trans had a completely failed 3/4 clutch.
However if the car moves fine with the trans connector disconnected, and especially if it then accelerates fine once the engine is in its power band, the 3/4 clutch might be OK.
However if you are having problems in 1st and 2nd too, then it is either a different problem or you have multiple problems.
One other thing disconnecting the trans connector does is cause the PCS (Pressure Control Solenoid) to go to max pressure. It could be that when plugged back in that the pressure drops to a very low level. Very low pressure will cause even 1st to slip and 3/4 not to work at all. This is currently my hypothesis.
Hence hooking up the mentioned pressure gauge would give us very useful diagnostic info. If the pressure is real low, I will then give you things to check that don't require removing the trans. It could be the pump (which would require removing the trans), but it could be a bad PCS, missing boost valve or bad valve body, all of which can be checked without removing the trans.
However if the car moves fine with the trans connector disconnected, and especially if it then accelerates fine once the engine is in its power band, the 3/4 clutch might be OK.
However if you are having problems in 1st and 2nd too, then it is either a different problem or you have multiple problems.
One other thing disconnecting the trans connector does is cause the PCS (Pressure Control Solenoid) to go to max pressure. It could be that when plugged back in that the pressure drops to a very low level. Very low pressure will cause even 1st to slip and 3/4 not to work at all. This is currently my hypothesis.
Hence hooking up the mentioned pressure gauge would give us very useful diagnostic info. If the pressure is real low, I will then give you things to check that don't require removing the trans. It could be the pump (which would require removing the trans), but it could be a bad PCS, missing boost valve or bad valve body, all of which can be checked without removing the trans.