TYPICAL TECHNICAL PROPERTIES
AMSOIL Long Life Synthetic Gear Lube 75W-90 (FGR)
Kinematic Viscosity @ 100°C, cSt (ASTM D-445)	15.9
Kinematic Viscosity @ 40°C, cst (ASTM D-445)	122.6
Viscosity Index (ASTM D-2270)	138
Brookfield Viscosity, cP (150,000 Max)	92,325 @ -40°C
Flash Point, °C (°F) (ASTM D-92) 150°C Min.	212 (414)
Pour Point, °C (°F) (ASTM D-97)	-51(-67)
Copper Corrosion (ASTM D-130) 1b Max @ 121 °C (250°F) / 3hr	1b
Falex Procedure B (ASTM D-3233) (failure load, lbf.)	1500
Foam Stability (ASTM D-892) (20/50/20 maximum)	0/0/0

For product service life in differentials, consult your owner's manual or the Original Equipment Manufacturer (OEM) to establish the application, NORMAL or SEVERE.

	NORMAL	SEVERE
Cars, SUV, Light Trucks	Drain at 100,000 miles of service or according to the owner's manual, whichever is longer	Drain at 50,000 miles of service or according to the owner's manual, whichever is longer
Heavy Duty Class 8 Line Haul	Follow the OEM drain interval (miles or hours) for synthetic oil up to 500,000 miles or three years, whichever comes first. Otherwise, drain at twice the OEM interval for petroleum oil.
Heavy Duty Off-Road Vocational	Follow the OEM drain interval (miles or hours) for synthetic oil up to 120,000 miles or one year, whichever comes first. Otherwise, drain at twice the OEM interval for petroleum oil.

For product service life in non-differential applications, consult owner's manual or the OEM for either normal or severe synthetic oil service intervals. Where service intervals are unavailable, drain at twice the interval for conventional oil. Note: AMSOIL does not support extended drain intervals where water contamination occurs. Check and service the gear oil frequently when water contamination is possible. Gear oils should be changed more frequently when operating vehicles or equipment in dusty or dirty conditions unless the gear system is properly sealed and equipped with membrane type breathers. AMSOIL LONG LIFE SYNTHETIC GEAR LUBES are compatible with conventional gear oils, however mixing oils reduces the benefits and nullifies the extended service life recommendations. AMSOIL LONG LIFE SYNTHETIC GEAR LUBES are compatible with most limited slip differentials. If limited slip differential chatter occurs, add AMSOIL Slip-Lock™ friction modifier additive. AMSOIL LONG LIFE SYNTHETIC GEAR LUBE 75W-90 replaces competitors' 75W-90 and 80W-90 viscosity grades

Reviewed by Craig:

Will buy more .

Product speaks for its self

Item Reviewed: Long Life Gear Lube (FGR,FGO)

June 26th, 2019 at 10:59 pm

Reviewed by Joe:

Gear lube

Seems like a great product

Item Reviewed: Long Life Gear Lube (FGR,FGO)

June 22nd, 2019 at 7:55 pm

Reviewed by Dave:

good product

I have used this product in commercial outdrives for over 10 years. Good life and no broken gears in all those years

Item Reviewed: Long Life Gear Lube (FGR,FGO)

October 25th, 2018 at 9:03 pm

Reviewed by 1blkc5:

awesome stuff

Used it in the rear end of My toyota tacoma seems great can't beat the price compared to severe gear lube .

Item Reviewed: Long Life Gear Lube (FGR,FGO)

May 13th, 2018 at 10:42 pm

Reviewed by Wildman:

Poor Shifting in Cold Weather

I replaced the OEM oil in the manual transmission on a 2014 Subaru Outback at about 60K miles. In the cold weather it was difficult shifting from neutral to first and first to second gears when cold. Shifting improved when the temperature increased after driving several miles. Therefore, I cannot recommend this lubricant for the stated application.

Item Reviewed: Long Life Gear Lube (FGR,FGO)

May 12th, 2018 at 4:08 pm

Reviewed by bacholiver:

Great lube

Has always served me well in all my vehicles, whether its the engine, (gas and diesel) Transmission, or differential. I have lived in Florida and in Minnesota and have always had the flow needed to keep things lubed.

Item Reviewed: Long Life Gear Lube (FGR,FGO)

April 15th, 2018 at 5:38 pm

Reviewed by Stew:

Excellent products I just love them

I run it in everything I own

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

March 12th, 2018 at 4:49 pm

Reviewed by Brian:

I'm a return buyer

I bought this lubricant specifically for my 1962 Ford Galaxie to replace the O.E. 90 weight that was installed in 1962. I've used Amsoil products since 2005 and will never go back to conventional lubricant. Its been good to me all these years and my classic car likes Amsoil too. It has made a big difference for my classic.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

February 20th, 2018 at 12:00 am

Reviewed by Farmer:

Love the product

I do a lot of towing with my vechile, from pulling large wagons such as gravity wagons and livestock trailers. I live in colder climates and never have trouble with my engine turning over hard.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

February 5th, 2018 at 12:00 am

Reviewed by Speed41u:

Better than OEM

I started using this back in 2008 after speaking to a rep and someone who used the product he sold. I researched all of the findings and found the product to be superior to others.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

January 30th, 2018 at 12:00 am

Reviewed by Suzuki Man:

Awesome product

I used it his gear oil for my older 4 door Suzuki sidekick. And can really tell how great it works, quieter running gears, cooler temps. And last a very long time between changes.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

January 23rd, 2018 at 12:00 am

Reviewed by Jim:

Good products

I like all your products that i have tryed and will buy again

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

January 18th, 2018 at 12:00 am

Reviewed by Big Rich:

Out performs all other products! Can see the difference

Completly serviced my 2015 GMC Sierria Denali 4x4 and I can tell the difference! Transfer case is smoother! Engine quiter! Gives you a feeling of confidence you can do what the truck is built to do!

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

October 11th, 2017 at 12:00 am

Reviewed by Mitch:

Good stuff

I use in my Jeep Wrangler, rear differential!

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

August 4th, 2017 at 12:00 am

Reviewed by nitro:

good products

I believe fully that Amsoil synthetics are the class of the field in all applications , I use their engine and mix oils in my quads and jet ski , so I seen their extended life gear oil I had to get it for my pickup , it might sound like an ad , but , Amsoil is all good stuff 😊

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

June 25th, 2017 at 12:00 am

Reviewed by Mike:

Gear lube

Worked perfectly....

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

May 17th, 2017 at 12:00 am

Reviewed by Mike:

Excellent product

Excellent product. The only fluids I use on my car and trucks.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

May 3rd, 2017 at 12:00 am

Reviewed by Atec:

Best gear oil

Setup gears and lockers for off road use. Always recommend or install Amsoil gear lube after my work is done. Feel very confident in a successful job especially when using this lube.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

February 19th, 2017 at 12:00 am

Reviewed by Seth:

Better than off-the-shelf shelf

Use it in our work vehicles. After the discount it's cheaper than any auto store

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

February 12th, 2017 at 12:00 am

Reviewed by Rich:

Confidence in Amsoil

It's difficult to give a review of a long term oil such as differential lube. But, Amsoil in my 4.2 and my 4.0 Jeep engines was immediately noticed. Jeep in-line 6 motors tend to have valve noise on start up. Totally gone now ! Love that Amsoil ( 10w30). Now switched all 3 Jeeps to Amsoil

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

January 28th, 2017 at 12:00 am

Reviewed by Steven:

Lang lasting fluid, it does as it's discribed

This really do last a long time and no issues with over 50,000 miles since changing my rear differential and transfer case and the fluid is still clean.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

December 26th, 2016 at 12:00 am

Reviewed by David:

Lasts longer than conventional gear oil-worth the extra cost

Put this in my 2wd Tacoma open differential, 10,000 miles so far and no issues. I purchased the premium AMSOIL synthetic product for its superior quality and long service life... will last longer and protect my vehicle better than conventional, so in the long run it's definitely worth the added cost.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

December 18th, 2016 at 12:00 am

Reviewed by Slick mike:

Diff fluid for 90 wrangler

I'm 60 years old and have used every possible lubrication known to man, Mail is by far the best.

Item Reviewed: 75W-90 Semi-Truck Gear Lube (FGR)

August 30th, 2016 at 12:00 am