Go look at your shift charts and make sure the downshift for that gear doesn't overlap the upshift from the gear below.
There needs to be a decent gap on every one, also, I go back and make sure the shift charts end up right at or below the WOT setting, so there is no discerpancy.
For example, here is one of my regal shift parameters...
The WOT shift..
is what makes the black lines on the shift charts...always make sure they coincide so you don't have differences. Also, check that the gray lines and the colored lines don't overlap, that will cause issues, you can make the gaps bigger, but not smaller. You can also see the red shift lines end up at or just below the black WOT lines approaching 100% throttle.
Unless you purposely don't want it to shift, as I don't want it to shift to 4th at WOT, so I make it so it doesn't. I would have to change that if I ever did a 1/2 mile or something, but it can go 165 MPH in 3rd so I'm good for the quarter with my 3.60 gears. Anyway, just some examples.
