2020 camaro 10l80 going into neutral while driving p0741 code T87a TCM

[lbz34]

COrcle D just installed the new looser stator in the converter, now we are getting a "neutral" between shifts. Had Circle D converter last year and never say any problems. ran great, just upgraded to the new looser stator in the converter and we are seeing this neutral problem. it seems to be most prevalent on the 4-5 shift but it will do it on 6-7 or 3-4. If we kill the code it wont limp mode anymore but will still do the in and out of gear thing its doing. If you look at the log it looks like the tcm is firing the tcc solenoid right before it does the neutral thing. Have tried never locking the converter and locking it very early (30 mph), doesnt seem to matter. Tried manual mode and auto mode, seems to do it less in manual mode but will still do it. I have seen the Drive indicator blink but it usually doesnt blink when it does it, but has a couple of times. fluid is full, double checked to make sure that wasnt the problem. trans neutral log.hpl

I did read about the new table in the t93 tcm's for the loose stall convterters but looks like the 87a tcm's dont have that table. It is very possible it is the converter causing this or possibly something new with the software? Anyone have any experience with this?

[TransGo Robert]

COrcle D just installed the new looser stator in the converter, now we are getting a "neutral" between shifts. Had Circle D converter last year and never say any problems. ran great, just upgraded to the new looser stator in the converter and we are seeing this neutral problem. it seems to be most prevalent on the 4-5 shift but it will do it on 6-7 or 3-4. If we kill the code it wont limp mode anymore but will still do the in and out of gear thing its doing. If you look at the log it looks like the tcm is firing the tcc solenoid right before it does the neutral thing. Have tried never locking the converter and locking it very early (30 mph), doesnt seem to matter. Tried manual mode and auto mode, seems to do it less in manual mode but will still do it. I have seen the Drive indicator blink but it usually doesnt blink when it does it, but has a couple of times. fluid is full, double checked to make sure that wasnt the problem. trans neutral log.hpl

I did read about the new table in the t93 tcm's for the loose stall convterters but looks like the 87a tcm's dont have that table. It is very possible it is the converter causing this or possibly something new with the software? Anyone have any experience with this?

This is really odd, I don't know why it is doing that but the computer is commanding it to go back to first gear which feels like neutral. it is as if when it sees that the TCC slip is so high from the higher K factor of the converter it then concludes it takes too long to drop it, set the P0741 and then momentarily put the unit is basically neutral before going back to commanding 5th gear a bit later. Hopefully someone can figure out what can be changed in the tune to stop it from doing that. When you set it to never command lock-up, does it still to do it at times, or not?

[lbz34]

It would still do it if we left the converter unlocked. Think it's sorted out now though. Looks like it is a table or setting with the back end stuff.

Definitely nothing to do with the converter, it was always locking solid when commanded.

[TransGo Robert]

It would still do it if we left the converter unlocked. Think it's sorted out now though. Looks like it is a table or setting with the back end stuff.

Definitely nothing to do with the converter, it was always locking solid when commanded.

Good deal, hopefully you'll share the fix with the rest of us. I would love to see the before and after tune as well as a log of it once fix.

[GHuggins]

I'm just getting going on this one, but it was my fault Robert. I can admit when I screw up I killed the misfire test - yep you read that right and that's what caused the trans to do this. Never seen that before but the 10 speeds apparently don't like it... I don't understand why it was "needing" to run that test or have it in the picture for the transmission unless it's just something associated with it's torque management routines, but nonetheless, it's sorted... Just have to get everything dialed in as that posted log was a very rough initial base tune.

[TransGo Robert]

I'm just getting going on this one, but it was my fault Robert. I can admit when I screw up I killed the misfire test - yep you read that right and that's what caused the trans to do this. Never seen that before but the 10 speeds apparently don't like it... I don't understand why it was "needing" to run that test or have it in the picture for the transmission unless it's just something associated with it's torque management routines, but nonetheless, it's sorted now... Just have to get everything dialed in now as that posted log was a very rough initial base tune.

That's very interesting and good to know. Thanks for taking the time to give details about what caused it.