The product of choice for those who know their gear oil. Redline MT-90 75W90 is a full synthetic gear oil that is rated for GL-4 applications. It allows for faster shifts and provides excellent protection in extreme track and street use. Redline MT-90 75W90 is excellent in new and old gearboxes/transaxles and improves shift feel, while providing the ultimate protection. Is your 1st or 2nd gear synchro wearing out? Hard to get it into gear on cold days? You'll definitely notice a difference when you switch to Redline MT-90. This is a Speedlife favorite.