This product dampens transmission noise (reducing the notorious shifting clunk found in these gearboxes) dramatically reduces temperature provides thicker oil films between gear teeth and resists throw-off for all aftermarket versions like baker jims s&s etc. For all h-d trans including with evolution engines twin cam engines and latest 6-speed cruise drive same fluid as our unique heavy shockproof gear oil motor oils and gear oils are specifically engineered for the latest high-revving four-stroke motocross bikes and atvs sport bikes and v-twins each gear oil product reduces the thinning effect from high temperatures motor oils are packed with higher levels of anti-wear chemistry like zinc and phosphorus special friction modifiers in our motor oils better wet-clutch operational variety of two-stroke oils to meet the nmma tc-w3 regulations where required.