I'm curious as to why anyone would use ShockProof oil in a Protege M/T since Red Line specifically warns against its use here. Red Line makes three classes of oils for M/T cars: Synthetic M/T lubricant (MTL and MT-90); Synthetic Gear Oil; and ShockProof Gear Oil.
According to Red Line, MTL and MT-90 are the recommended oils for M/T's with synchronizers as they have the appropriate coefficient of friction for most M/T synchronizers. Red Line claims that many gear oils, engine oils and ATF's are too slippery for proper synchro engagement.
The ShockProof oils (SuperLight, Lightweight and and Heavy ShockProof) are not recommended for synchro-type transmissions as Red Line considers these oils too slippery for optimal synchro engagement.
In the Gear Oil category, with one exception, these oils are also not recommended for the same reason-they are too slippery and thus prevent rapid synchronization. The one exception is 75W-90NS because, according to Red Line, "this gear oil doesn't contain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers come to equal speeds more quickly, allowing faster shifting and much easier low-temperature shifting."
Based on the foregoing, why use anything but the manufacturer-recommended oil?