Lubegard 70944 Heavy Duty Gear Protectant, 32 fl. oz.

UPDATE 02-21-2017: I drained the Lucas Synthetic 75w-90 and was pleased that I did because the magnetic drain plugs on the front and rear diffs had accumulated quite a bit more ferrous material (no doubt it was generated before the Lucas was installed and the fresh fluid simply 'washed' the inside of the diff case and carried it to the drain plug; not Lucas's fault at all).I installed Mobil-1 75w-90 full syn gear oil and the Lubegard HD Gear protectant in the proscribed proportions. Previously, my wife had been seeing average MPGs of 22.8 - 23.4, week over week (same commute, same gas, same gas station). After installing this last weekend, her average MPGs have risen to 24.8 after conducting a reset of the trip computer. She even observed it hover near 25.5 until an unusual traffic jam hurt her average that day. She also mentions better coasting down from about 70mph to 40mph, and better throttle response to boot while locked-up in 5th gear (top gear). Considering that the Lucas is apparently a channeling gear oil (bad; you want a non-channeling oil) and runs more toward the 110-weight end of the gear oil spectrum (it's been tested to be out-of-grade, on the HIGH end, for 90 weight gear oils), the upgrade was for the better.Regardless, no LSD chatter which was brought on by heat alone since this subie uses a sealed Viscous LSD unit that has silicone fluid sealed inside of the differential unit inside the carrier....so the only thing that could have caused the chatter was heat. This additive reduces heat and that's always a good thing.I can also confirm that, unlike gear oil, it simply does not come off of your hands. Use gloves. Even with Orange Oil Pumice super ultra volcano hand scrubber soap with miniature hand scrubbing machines. I can get Mobil 1 gear oil off my hands with regular garage soap; but not Lubegard HD....nope. Not with any soap or chemical I was willing to apply to my skin. Not dirt. Not sand. Not ash.So, it's slippery stuff and is designed to go the full service interval of the gear oil. EXCELLENT!!!**********************************************************************************************I added this to my 2011 Subaru Outback 3.6R Limited's front and rear differentials, which already had Lucas 75w-90 Synthetic gear oil in them. I still occasionally encountered gear noise when on the highway or when cold, though the Lucas did stop the rear LSD chatter when making U-turns.The Lucas will be exchanged for Mobil-1 75w-90 in a few weeks because I recently discovered via my research that the Lucas runs above a 90 weight and is more like a 110 weight gear oil. Also, the Lucas permits "channeling", which the Mobil1 does not. Just google it.Regardless, after applying the proscribed amount of Lubegard, diff noise is gone.

Not a fan of "snake oil additives"... but I am a fan of "science and using things that work"I bought this to try on our new 2017 Subaru Forester XT, used on the 1,000 mile break-in oil change, I have used the Bio-Tech Engine additive before several times on my fleet of vehicles always with good results, lower temps, quieter, and a bump (up) in MPG always followed after adding LubeGard products to my vehicles... so I figured it was time I branch out and try the Gear Protectant in the car also :)No funny noises after 'replacing' 3 ounces per quart of Mobil 1 75w-90 with LubeGard... took about 1.5 quarts of gear oil mixture for the front diffy and barely 0.8 quarts fit in the rear... with LubeGard being known for "lowering temps", I figured any help I get get to keep the small capacity diffs cooler I would gladly try it out.I will report back after several tanks of gas for a good "Fuel Economy" report but here is what data I have so far:1st tank, 25.31 mpg2nd tank, 26.49 mpg (had 2 ounces of Bio Plus added to the fuel)3rd tank, 27.21 mpg (had 1 ounce of Bio Plus)4th tank, 28.75 mpg (had 2 ounces Bio Plus, Castrol 0w-40 + LubeGard, Mobil 1 75w-90 + LubeGard, and a AEM dry flow air filter)5th and 6th tank averaged around 30.84 mpg between them... about 22 percent better fuel economy over the first tank of fuel... everything I've done is saving me about $9 for every full tank of gas I get** Edit ** Added this to my mom's 2009 Subaru Impreza with a manual transmission yesterday (without her knowing I added it)... today she asks if I did any work to the car, "it's driving and shifting smoother", I only added about 3oz per quart of transmission oil and she knew instantly it worked...My "single blind study" on mom's Subaru confirmed this stuff works ;)

Makes differentials and gearboxes run cooler and smoother.

I bought this product based on my experience with their transmission and engine products, which absolutely work. I have a 1991 Nissan 300ZX, and it made the transmission quieter.