It is generally believed that a stiffer shift is the measure of a transmission's performance and durability. That is only true if the slippage was prolonged enough to cause excessive temperature of the friction materials.Otherwise a stiffer shift does not add any performance or durability. Additional stiffness REDUCES performance and durability if the additional firmness includes interference or overlap. Stiffness during the 2-3 shift is almost always overlap. Overlap is the condition of applying a gear before the previous gear has been released. Nothing is harder on friction materials (clutches & bands) than to apply them in opposition of each other.

Calibration kits are designed to improve the performance and durability of today's automatic transmission by furnishing additional oil flow to areas of warp and wear, and exhausting the crossleaks that often cause friction failure. Re-calibration of the control assemblies provides a shorter, firmer, more precise shift, eliminating overlap for increased performance and fuel economy. You will obtain better control of gear selection while maintaining automatic shifting in "D". You can have manual low at any speed! Great for motor homes, towing, high performance, and many other applications. Increase the life of your tranmission by installing a calibration kit today!

There are 3 major suppliers of calibration kits. I have listed them below;