Axle Gear Oil

Unanswered topics | Active topics

Home » Board index » Tech Q & A » Transmission & Rearend

All times are UTC-08:00

Post new topic Reply to topic

Page 1 of 1

[ 2 posts ]

Print view

Previous topic | Next topic

Author

Message

FrankRaso

Post subject: Axle Gear Oil

PostPosted: Wed Jul 11, 2012 8:25 am

Offline

Turbo Slant 6

Joined: Fri Apr 16, 2004 10:50 am
Posts: 660
Location: Stevensville, ON
Car Model:

I've been working on making sure that I am up-to-date with the scheduled maintenance on my 65 Barracuda. Since I installed a 7-1/4 axle from a 74 Duster, I thought I should put some fresh gear oil in the axle. My 1965 owner's manual recommends API GL-4 while my 1975 FSM recommends API GL-5. I am thinking about using a 75W-90 GL-5 oil in my axle with a new Felpro RDS12775 gasket.

Robert Michell suggests in his book "Which Oil?" that GL-5 may be unsuitable for some applications. He writes the following:

Quote:

To give the EP [extreme pressure] performance, most GL-5 lubricants use compounds that contain sulphur and sulphur is chemically very aggressive to what are sometimes called the "yellow metals". These nonferrous metals include copper and alloys of copper, such as bronze. ... The visual appearance of such chemical attack can vary from glazing to corrosion or pitting of the metals concerned.

Has anyone had any issues with using an API GL-5 hypoid gear oil in their axles?

Top

Profile

Reply with quote

Joshie225

Post subject:

PostPosted: Wed Jul 11, 2012 12:17 pm

Offline

Supercharged

Joined: Thu Jan 27, 2005 8:32 pm
Posts: 7834
Location: Portland-ish
Car Model: Fiat 500e

No yellow metals in the rear end so GL-5 is fine. Good even. Yellow metals include transmission syncronizer rings and GL-5 can eat them in certain circumstances. Usually the largest problem with GL-5 in a manual trans is slow/difficult shifting. Rear axles have no such issues.

_________________
Joshua