i have a 2002 camaro built, and a aftermarket 4l60e with 3500 stall.. The car shfts good when driving it normal but go to wide open throttle and it goes to ****... i shift 1-2 fine 2-3 is the problem, my tuner has set the shift point at 6200 and it cranks to 6500. It wont shift until you you let off the gas... The tranny does have a vac. modulator on it. Any body know whats going on

 

Could be excessive 3-4 clearance or 300 rpm depending on your power level may also not be enough time to make the shift. You see really shift time should be measured in time to rpm. For instance if a car has X amount of power and you set it to shift at 6200 and it makes the shift at 6300, Then if you take another car all things equal even the same trans and it has 100 hp more, it while the trans will still be doing the shift in the same time period it did before .Now the engine has more power the RPM are rising at a faster rate so more time may need to be allowed, I would increase the spread a bit more before I did anything and see what happens, I have seen guys post that in some instances they needed 500 even 600 rpm to make the shift on the 2-3 because hydraulically its a much more complicated shift than the 1-2 shift.Also remember not only do the RPM need to me met but a speed setting also must be met in order for the shift to occur.

 

but its like it tring to shift because when it his 6500 to 6700 it stops cranking, not hitting the rev limiter then i let off the gas and it shifts

 

Well the big thing is to see if the shifts actually being commanded when it supposed to
being programed to shift at a certain RPM and actually dong it are two different things for the PCM first .

 

so your saying set the shift point lower and see if it shifts

 

Yes thats it