How can I recalibrate my automatic tranny shift points with a gear swap?
The only way to do it is to reprogram the ECM or replace the computer chip. As for aftermarket chips/programs, most of them which adjust the speedometer for gear changes, also modify tranny shift points at redline for wide open throttle. However the problem with these chips is that they don’t modify the shift points under partial throttle. Since shorter gears (which are numerically higher, like 3.73) rev higher, the stock computer program/chip will still be shifting at its preset points. So the engine may hit 3000 or 4000 RPM before shifting (whereas before it would shift at 2000 RPM). Some people believe there is a Federal law which prohibits modification to the stock partial throttle shift points on automatic transmissions (most likely related to emissions), but this is possibly only rumor. Try contacting your chip/program company of choice and check with them about a custom set-up.
