I thought that was funny, my stage 4 FLT just started doing the same thing...

 

There are many possible causes for this , While yes it can be the trans, It can also be tuning and even enviromental factors. The trans often get blamed when its not the cause, Thats why we have test equipment we can send our customers to help determine this. I will say alowing it to continue doing it will indeed cause a trans problem

 

I have spent a lot of time tuning my built transmission. We know that you have lowered the shift RPM. It takes two things working together for the computer to command a shift. One being RPM and the other is MPH. Some cars respond better to the MPH than RPM. THe way I set up my shifting tune is to set RPM at the maximum that I would want car to shift. I then play with the MPH for the commanded shift to dial it in. My tranny shifts 1-2, 2-3, 3-4 within 50-100 rpm @ WOT on motor and within 100-200 rpm on a 150 hp shot. Being that it is a stock rebuild, it could use a rebuild with some upgrades. Good clutches set up with tighter tolerances and a good reverse clutch drum with a Red Eagle wideband or a carbon wideband to start.