1-2 shift hits limiter every time

Hey guys I need some help. I have a 99 Trans Am with the 4L60E transmission in it and am having a issue with tuning the shift since changing the rear gear. I had my car tuned for H/C/I/H and a 3200 Yank Stall, it also had the stock 2.73 gear in it. When running at no prep events I could drive the car 1st,2nd,3rd and that would allow me to pedal for tire spin without short shifting into 2nd if the car was in "D:

So I changed nothing on the car except of the rear gear. I went from the 2.73 to a 3.42. Since doing that tire spin has got worse for obvious reasons. When I try to drive the car 1st, 2nd, 3rd it bangs off the limiter every time on the 1-2 shift, but not on the 2-3 shift. If I leave it in "D" and hammer it the trans shifts 1-2 perfectly. I have adjusted the tables for the new gear ration, adjusted the shift speed and rpm, adjusted the limiter. I also sent it back to my tuner and he cant figure it out either.

Any help would be appreciated

To shift, the PCM needs to meet 2 parameters - RPM, and Speed. BOTH must be met for the car to shift. However, note that when the trigger is met, it can take a little bit of time for the shift to occur, so many go under about 5 MPH and set the RPM 100-200 under the intended shift point. To determine how fast the car goes at whichever gear, you can hold the gear and do it that way, or simply set the triggers much lower than intended and work up to what you want.

I use RPM as the trigger for my shifts, so I set the MPH much lower, since it won't shift anyway until it hits the RPM at whatever throttle %. Also, make sure your WOT shift points match your other tables at the end, so as not to confuse that poor old PCM.

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Originally Posted by ChopperDoc

To shift, the PCM needs to meet 2 parameters - RPM, and Speed. BOTH must be met for the car to shift. However, note that when the trigger is met, it can take a little bit of time for the shift to occur, so many go under about 5 MPH and set the RPM 100-200 under the intended shift point. To determine how fast the car goes at whichever gear, you can hold the gear and do it that way, or simply set the triggers much lower than intended and work up to what you want.

I use RPM as the trigger for my shifts, so I set the MPH much lower, since it won't shift anyway until it hits the RPM at whatever throttle %. Also, make sure your WOT shift points match your other tables at the end, so as not to confuse that poor old PCM.

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I have done all of that. Still no luck. I just found the BlueCat transmission table, I am going to try that tonight

so it only over revs when shifted manually from 1st to 2nd?

Correct

stop trying to manually shift it then lol

I have my 1-2 set around 5400 and I get a 5800rpm shift most of the time- but sometimes its 5900 and sometimes its 5650. It depends how fast the engine is accelerating at that moment (rate of change of angular velocity)

So when you swapped gears you made the engine accelerate faster. And the computer to transmission 'speed' hasn't gotten any faster so