No downshift around corners - 700r4

I have a 1988 Camaro iroc with the 700r4 trans. As far as i know nothing has been replaced, rebuilt, and its the way it rolled off the showroom floor.

My problem is everytime i go around a turn, the trans wont shift down into the correct gear. It stays one gear higher than it should be. In order for me to correct it, i have to give it a bit more gas to make is downshift into the right gear.

It also does it sometimes if i slow down really fast (say from 45mph to about 15mph) and then get back on the gas, the engine will labor. i have to step on the gas to make it shift down because its a gear higher than it should be.

Other than that the trans works flawlessly.

The fluid is full

The tv cable is set correctly (its tight at WOT)

I have no idea what to do...please help!

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1988 Camaro Iroc-Z - 76K All orig.
1994 Honda Magna
2004 Civic Ex

You could remove the lighter spring that is in the governor. It has "two" springs in ther, remove the weaker of the two springs and see what happens. If this does not solve it you can add the TransGo TV (Shift kit) system, but this will require that you remove the valve body. Your transmission sounds pretty much normal from past experiences.