Copied from the Spectro site. I just changed to Spectro trans oil and now I find they recomend to change it every 5K. How do you guys feel about this? Do you change it every 5K? Just wondering. Thanks Product Information Heavy Duty Platinum 6-Speed Transmission Oil There Is More To A Transmission Than Just Metal As a company tenaciously focused on any improvement to the American Big Twin drivetrain, BAKER Drivetrain recognizes the fluid in the transmission is key in the performance and life of a transmission. It is a mechanical part of it as much as the gears, case, bearings, etc…so it must be of quality. The Spectro Platinum Heavy Duty 6-Speed Transmission Lubricant meets our BAKER Drivetrain quality standards for recommended transmission oil. Our standard for recommending oil is that it must have optimized properties tailored only for components in a V-Twin motorcycle transmission and it must exceed all others in excellence – like our own products do. Cheaper oils cannot provide all these qualities. Spectro’s 6-Speed formula base is synthetic group 4 base stock which is the highest rating for a synthetic lubricant. It is pure with absolutely no petroleum product blended into it. Unlike most others, the oil carriers for the anti wear and friction modifiers are 100% synthetic making this oil truly 100% synthetic which means this fluid cannot be worn out or broken down - it can only be contaminated. For example, in a hermetically sealed application it would last for 20 years, but transmissions are far from sterile because the vent breathes air as the transmission heat cycles and the seals are not perfect. For this reason, we advise changing your oil every 5000 miles or once yearly, whichever comes first. It’s worth the investment protecting your premium transmission. All anti-wear ingredients are additized to a factory fill specification. Additives include zinc as an anti-wear additive, phosphorous as an anti-wear and friction modifier, and sulfur as an anti-wear and friction modifier. Note; sulfur cannot be used as an additive in multi-use oils that are used in the engine sump because sulfur gets contaminated by the combustion process and eventually changes into sulfuric acid. Spectro’s special formula also protects against long term seal leaks by maintaining seal elasticity, as validated by Buna-N testing. As drivetrain innovators we are proud to be the ones to discover, introduce, and endorse this lube. We are equally proud to announce that Spectro 75W140 is approved by BAKER Drivetrain for use in all BAKER transmission products and we reflect that by including a free bottle in our DD6 transmissions for your best performance and convenience.