Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Thinner differential oil for RWD car? ('06 Miata)

Bror Jace · 10-10-2011, 12:24 AM

One problem you are going to have is not so much the viscosity as it is the additive package. For a diff, you'll want a GL5 add-pack.

Syncromesh, Red Line MTL, Amsoil MTF and the like are GL4. I don't believe any of those are dual rated GL4/5 ... but some 75W-90s and 80W-90s are.

For really thin rear-end gear oil, I might try this stuff:

Red Line Synthetic Oil - Gear Oil for Differentials - 75W85 GL-5 Gear Oil

or:

Red Line Synthetic Oil - ShockProof® Gear Oils - Lightweight ShockProof®

The Superlight Shockproof is likely too thin for proper durability.

I think with a Miata, though, you're #1 enemy is wind resistance. I love my convertible, but it's an affront to the aero gods.

10-10-2011, 12:24 AM	#10 (permalink)
Bror Jace Recycling Nazi Join Date: May 2008 Location: People's Republic of Albany Posts: 234 Blue Bullet - '06 Honda Civic Sedan LX 90 day: 35.68 mpg (US) Thanks: 2 Thanked 7 Times in 7 Posts	One problem you are going to have is not so much the viscosity as it is the additive package. For a diff, you'll want a GL5 add-pack. Syncromesh, Red Line MTL, Amsoil MTF and the like are GL4. I don't believe any of those are dual rated GL4/5 ... but some 75W-90s and 80W-90s are. For really thin rear-end gear oil, I might try this stuff: Red Line Synthetic Oil - Gear Oil for Differentials - 75W85 GL-5 Gear Oil or: Red Line Synthetic Oil - ShockProof® Gear Oils - Lightweight ShockProof® The Superlight Shockproof is likely too thin for proper durability. I think with a Miata, though, you're #1 enemy is wind resistance. I love my convertible, but it's an affront to the aero gods. __________________ --- Bror Jace