# Gear Oil Question



## Scarecrow1 (Sep 3, 2016)

I have a 2000 Nissan Altima 5 speed Manual Transmission. My owner's manual says use api gl4 80w-90 gear oil. Can I use gl5 instead? Is that safe? I'm reading conflicting posts about in online. Thanks.


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## smj999smj (Jan 1, 2006)

You can only use GL5 if it states that it is "safe for yellow metals." If it doesn't say that, don't use it. There are several options for GL4 gear oil. Sta-Lube (made by CRC) has 85W90 GL4 gear oil in one gallon jugs; you can get it on Amazon if you can't find it at your local auto parts store. It's expensive, but Red Line and Amsoil make synthetic GL4 75W90 gear oil that is sold in quarts and gallon containers (see links below). The problem with most GL5 gear oils is that they contain sulfur, which can damage the brass synchronizers inside the transmission. 





https://www.redlineoil.com/product.aspx?pid=46

AMSOIL Manual Transmission & Transaxle Gear Lube 75W-90


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## smj999smj (Jan 1, 2006)

You can only use GL5 if it states that it is "safe for yellow metals." If it doesn't say that, don't use it. There are several options for GL4 gear oil. Sta-Lube (made by CRC) has 85W90 GL4 gear oil in one gallon jugs; you can get it on Amazon if you can't find it at your local auto parts store. It's expensive, but Red Line and Amsoil make synthetic GL4 75W90 gear oil that is sold in quarts and gallon containers (see links below). The problem with most GL5 gear oils is that they contain sulfur, which can damage the brass synchronizers inside the transmission. 





https://www.redlineoil.com/product.aspx?pid=46

AMSOIL Manual Transmission & Transaxle Gear Lube 75W-90


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## Scarecrow1 (Sep 3, 2016)

Thanks for your expert advice! I bought Brad Penn 023-7729 80W-90 GL4 Gear Lube - 1 Quart, (Case of 12) on Amazon 
(https://www.amazon.com/gp/product/B009I9CAJS/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1). It was $65 for a case of 12 quarts.

Follow-Up Question: 
What is your opinion of adding Bardahl 3119 Gear Oil Additive Plus Stop Leak (https://www.amazon.com/Bardahl-3119...3_4?ie=UTF8&psc=1&refRID=DMG73QPDMEN7NG84HVYN) to try to seal a very, very small manual transmission leak? 

I was also considering ATP AT-205 Re-Seal (https://www.amazon.com/gp/product/B000NVW1LM/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1), but then I read some scary reviews by some people who wrote that it made their leaks much worse.

Thanks for your help!

(The car is old but runs well, and I'm just trying to keep it alive for about another year before I donate it to a charity.)


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