The transmission seems to disconnect for just a moment in a left turn and only in a left turn. The fluid is topped and clean. It is a Borgwarner Type 35 Auto box. The car is beautiful otherwise.
I assume your statement “The fluid is topped…” means you have set the fluid level at the upper ‘hot’ level line with the engine running, car on a level surface, and after shifting through all the gears. The next thing to look for is an air leak in the pump inlet path. Check the gasket and tighteness of the filter screen in the pan. At the same time check the tightness of the valve body to case screws. Concentrate on the left side in your search for the air leak. If this does not solve the drop out, put a pressure gauge on the line pressure tap; drive it until you get the drop out; and see if the pressure has dropped with the slip and returned with the reengagement. With further diagnostic information get back to this site and see if we can help further.
You’d notice this if you were under the car, but you don’t happen to have a big ol’ dent in your transmission pan, do you?
I will check it out and let you know.
The Trans pan is a cast one and it has no dents at all.