Can API GL-4 Transmission Oil Replace GL-3 Oil?

A reader asks: I’m looking for an API GL-3 manual transmission oil for my 2006 Pontiac Solstice. GL-4 transmission oil is widely available, but I can’t find GL-3 oil anywhere. Do you have an oil that will work?

Our answer: Yes, we do have a product that is safe for manual transmissions requiring an API GL-3 fluid. AMSOIL Synthetic Manual Transmission and Transaxle Gear Oil is rated as an API GL-4 oil. However, this product is safe and appropriate for use in manual transmissions requiring an API GL-2 or GL-3 oil.

It is important to note that all transmission oils meeting the API GL-4 specification are safe for applications requiring a GL-3 oil.

What Is The Difference Between GL-3 And GL-4 Transmission Oil?

Transmission oils carrying the API GL-4 specification offer more extreme pressure wear protection compared to the requirements of the GL-3 specification. However, GL-4 oils are still safe for yellow metals such as brass synchros.

How Is the GL-4 Synthetic Manual Transmission and Transaxle Gear Oil Safe For GL-3 Applications?

A main concern with choosing an oil for manual transmissions requiring a GL-3 gear oil is its compatibility with yellow metals. For example, copper, bronze and brass are categorized as yellow metals.

Products like AMSOIL Synthetic Manual Transmission and Transaxle Gear Oil are suitable for GL-3 applications because its additive chemistry is very stable at high temperatures. Extreme pressure additives have to be utilized correctly so that they offer protection without causing yellow metal corrosion. The AMSOIL product’s sophisticated formula delivers both exceptional wear control and yellow metal preservation.

Why Doesn’t AMSOIL Include “API GL-3” On The Synthetic Manual Transmission and Transaxle Gear Oil Label?

AMSOIL does not list the API GL-2 or GL-3 specification of the data sheet or label of the Synthetic Manual Transmission and Transaxle Gear Oil product because these are long-obsolete industry specifications.

Where To Buy Synthetic Manual Transmission And Transaxle Gear Oil For API GL-4 And GL-3?

Oildepot can offer AMSOIL Synthetic Manual Transmission and Transaxle Gear Oil at great prices in both the United States and Canada. Contact us using the price list request form on this page.