Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Effect of gear oil viscosity on transmission efficiency (Metro owners take note)

Madact · 12-09-2014, 12:22 AM

Some more low-viscosity fully synthetics to add to the list (these two are manual-transmission specific oils compatible with brass & bronze synchros). Info unapologetically copied from data sheets, I'm sure the companies won't mind the free promotion

Penrite PRO GEAR 70W-75
Specifications: GL-4 Plus, ZF, TE-ML 11 (manual) MTF BOT 338 Tremec (T-56)
Typical Characteristics:
cSt 40oC 34
cSt at 100oC 6.9
Viscosity Index 171
Viscosity, Brookfield, cSt at -55oC 82,700
Zinc, mass % 0.131

CASTROL SYNTRANS FE 75W
Specifications: API GL-4, WSS-M2C-200-D2
Density @ 15C, relative ASTM D4052 g/mL 0.852
cSt 40oC 32.2
cSt 100oC ASTM 6.3
Viscosity Index 154
Viscosity, Brookfield cSt at -40C 10,000
Pour Point -51C
Closed Flash Point 226C

Redline "Shockproof Superlight" (may be incompatible with brass synchros) is claimed to "be rated as a 70W90 Gear Oil, but has the lower internal
fluid friction of an ATF".
[EDIT] There are some mixed opinions out there about shockproof, some say it may have high sulphur content, making it unsuitable for use with brass/bronze synchros. The redline site says the Redline "Shockproof Heavy" is unsuitable for synchros due to excessive slipperyness, but no firm statements either way on compatibility for the lighter grades. The "shockproof light" grade is also known as "smurf blood" (it's blue and expensive), many swear by it but others say it has bad long-term effects on synchros (sulphur issues and glazing). However, by some reports it may also temporarily resurrect a gearbox which is crunching gears. Redline MTL is specifically recommended for brass synchros, but isn't especially low viscosity (75W80).

Also, redline have an interesting article here which discusses effects on fuel economy and drivetrain efficiency:
Redline gear oil article

And another table of low viscosity transmission oils: http://www.red90.ca/rovers/MTF.htm

12-09-2014, 12:22 AM	#45 (permalink)
Madact EcoModding Apprentice Join Date: Aug 2014 Location: Adelaide, Australia Posts: 120 Emerald - '97 Honda Civic CXi 90 day: 40.13 mpg (US) Thanks: 53 Thanked 53 Times in 32 Posts	Some more low-viscosity fully synthetics to add to the list (these two are manual-transmission specific oils compatible with brass & bronze synchros). Info unapologetically copied from data sheets, I'm sure the companies won't mind the free promotion Penrite PRO GEAR 70W-75 Specifications: GL-4 Plus, ZF, TE-ML 11 (manual) MTF BOT 338 Tremec (T-56) Typical Characteristics: cSt 40oC 34 cSt at 100oC 6.9 Viscosity Index 171 Viscosity, Brookfield, cSt at -55oC 82,700 Zinc, mass % 0.131 CASTROL SYNTRANS FE 75W Specifications: API GL-4, WSS-M2C-200-D2 Density @ 15C, relative ASTM D4052 g/mL 0.852 cSt 40oC 32.2 cSt 100oC ASTM 6.3 Viscosity Index 154 Viscosity, Brookfield cSt at -40C 10,000 Pour Point -51C Closed Flash Point 226C Redline "Shockproof Superlight" (may be incompatible with brass synchros) is claimed to "be rated as a 70W90 Gear Oil, but has the lower internal fluid friction of an ATF". [EDIT] There are some mixed opinions out there about shockproof, some say it may have high sulphur content, making it unsuitable for use with brass/bronze synchros. The redline site says the Redline "Shockproof Heavy" is unsuitable for synchros due to excessive slipperyness, but no firm statements either way on compatibility for the lighter grades. The "shockproof light" grade is also known as "smurf blood" (it's blue and expensive), many swear by it but others say it has bad long-term effects on synchros (sulphur issues and glazing). However, by some reports it may also temporarily resurrect a gearbox which is crunching gears. Redline MTL is specifically recommended for brass synchros, but isn't especially low viscosity (75W80). Also, redline have an interesting article here which discusses effects on fuel economy and drivetrain efficiency: Redline gear oil article And another table of low viscosity transmission oils: http://www.red90.ca/rovers/MTF.htm Last edited by Madact; 12-09-2014 at 10:07 AM.. Reason: More info on redline shockproof.