If you believe you have gum, sludge, or varnish clogging up the transmission, B-12 Chemtool Fuel Treatment (part #0116) may help smooth out your shifting. This could be the case if the tranny was run low on ATF and excessive heat began breaking down the fluid. However, if the transmission has been well-maintained, i.e. always been kept full and had regular fluid and filter changes, then gum, sludge and varnish may not be culprits and such a treatment could do more harm than good by breaking loose clutch fibers, pieces of seal and gaskets, metal debris, etc. Based on your unique situation, if you choose to apply B-12 Chemtool, begin by changing the filter and fluid if possible in order to maximize the cleaning ability of the additives. Then pour into your cold transmission approximately 1½ oz. of #0116 per quart of ATF capacity. For instance, if the transmission holds 10 quarts, then you would use one entire 15-oz can of B-12 Chemtool. After you’ve added it to your cold ATF, start the car and drive it gently for 10-15 minutes allowing it warm up and to shift through all the gears several times. If you have time, you might want to let the ATF cool down and then repeat the treatment. Afterwards, change the spent fluid and filter.