Recalibrates your automatic transmission for optimum performance and extended lifeTwo kits in one box -- select Stage 1 for heavy duty applications, or Stage 2 for hi-performance street applicationsTransmission removal is not requiredRetains normal automatic operation with selector in "Drive"Backed by the manufacturer with a 1 year limited warrantyThe B&M Transpak kit can help increase the performance and durability of your stock automatic transmission. By eliminating many restrictive oil flow controls in the transmission's valve body, it allows the transmission to shift more firmly and reduce slippage and shift overlap, providing crisper shifts and reducing wear. Each kit gives you two modes of performance to select from -- heavy duty or hi-performance street. The heavy duty option gives street rods, normal passenger vehicles, and other heavy duty applications a firmer shift feel without a dramatic loss of comfort. The hi-performance street option is similar to the heavy duty option, but the shift is much quicker. Both options retain normal automatic operation when in "Drive".