There are plenty of options available while buying high viscosity gear oils in the market right now, and if you're confused regarding which one to go for, This page is just for you.

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Our Top Picks:

Best Overall: Buy: Red Line High Viscosity Gear Oil READ REVIEW

Best For Rear Differentials: Buy: Valvoline High Viscosity Gear Oil READ REVIEW

Best For Outboards: Buy: Quicksilver High Viscosity Gear Oil READ REVIEW

Best For Boat: Buy: Star Brite High Viscosity Gear Oil READ REVIEW

Best For Heavy Duty: Buy: Lucas Oil High Viscosity Gear Oil READ REVIEW

Best For Transfer Cases: Buy: Acdelco High Viscosity Gear Oil READ REVIEW

Best For Good Value: Buy: Ultra 1Plus High Viscosity Gear Oil READ REVIEW

Best For High Temperature: Buy: Royal Purple High Viscosity Gear Oil READ REVIEW

Best With Fastest Shipping: Buy: Lubrimatic High Viscosity Gear Oil READ REVIEW

Best Overall: Red Line High Viscosity Gear Oil

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The Red Line High Viscosity Gear Oil is long-lasting, rigid and fits well with your daily usage like a dream. The red line high viscosity gear oil is perfect for transfer cases, is perfect for great quality and it allows for huge improvement. Make sure this fits by entering your model number. And, it runs great, is great with great service and it is safe for brass synchros.

Above all, the red line high viscosity gear oil is used for shorter trips and it is highly recommend.

Almost all customers opine that the oil is not only gl-4 mt. And, they strongly agree that the oil is with outside temps of 85. And, a few also found that these older transmissions call for gl4 transmission oil, which is scarce, other than red line. To sum up, many have used the red line high viscosity gear oil for more than a few months without any complaints, and it shows no sign of giving up.

• It is very cold and the oil is working great.
• This is designed for different uses.
• This is making a grinding noise in 3rd gear.
• This allows for smoother shifting, is incredible and it has made shifting smoother.

Best For Rear Differentials: Valvoline High Viscosity Gear Oil

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The Valvoline High Viscosity Gear Oil's material feels more premium than its price would suggest. The valvoline high viscosity gear oil is single and it is used for heavy duty. High performance gear oil is an extreme pressure gear lubricant formulated with quality base oils and superior additives that helps protect against severe temperatures, shock loads, scuffing, scouring, corrosion and pitting at high speed, high load, high torque and high horsepower conditions. Further, it is because of this legacy that people have trusted valvoline products in their vehicles from the model to today's newest models. Most importantly, the valvoline high viscosity gear oil protects against severe temperatures to help extend service life.

Almost all customers quickly discovered that the oil is a torsen type diff and many others with those rear diffs complain about wine noise that can be cured with the heavier weight oil. And, they say that the oil is a mineral based gl-5 gear lube. Moreover, a few say that if the oil is the specified weight it should be fine. Overall, for almost all customers, Valvoline product was what they were looking for.

• This can ruin your sychros and the correct rating is "85w.
• Helps protect against gear wear from scuffing, scouring, corrosion and pitting.
• This oil is for your rear axle gear box.
• This is suitable for use in all 2000.

Best For Outboards: Quicksilver High Viscosity Gear Oil

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The Quicksilver High Viscosity Gear Oil's material feels more premium than its price would suggest. The quicksilver high viscosity gear oil is designed for outboard and sterndrive applications above 75 hp. Make sure this fits by entering your model number. In addition, it can be trusted for good quality and it is highly recommend.

Above all, the quicksilver high viscosity gear oil is great for a fair price and it works great.

Almost all buyers found that the oil is easy to use with a pump. In addition, they also found that the oil can be used in an outboard boat drive so it should work. In addition, they strongly agree that the premium gear lube is designated for use on the larger outboards.

• This looks like a chocolate milkshake, You have moisture getting into your gearbox.
• This comes out the same color as it came in.
• This is a great size for that and the cap seals well.
• The oil in question is colored, you wo n't know which is which.

Best For Boat: Star Brite High Viscosity Gear Oil

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The Star Brite High Viscosity Gear Oil might be a relatively new release, but it's still nothing short of impressive this year, thanks to multiple price cuts and added new features over the past few months. The star brite high viscositygear oil is designed for a great price and it is much cheaper. Make sure this fits by entering your model number. Further, the oil protects against rust and corrosion. Finally, the star brite high viscosity gear oil is full synthetic and it is at a nice price.

Most customers agree that the oil is an 80w90 lubricant, so it should be a good choice. And, a few also found that the oil was fully initial description does not note this. Moreover, a few strongly agree that note: if the oil is synthetic, which the label says it is, and the oil is viscosity is made for lower units, which the label says it is, then it should be good. To sum up, at the price, they believe that they got a steal of a deal with it.

• This can be used on twin 300 outboards.
• This is great with two mercury outboards lower units 9.9.
• It is easy to replace old oil.
• This is a gear oil for an outdrive on a boat, not engine oil.

Best For Heavy Duty: Lucas Oil High Viscosity Gear Oil

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If you often find yourself confused about appropriate and satisfactory oil, Lucas Oil High Viscosity Gear Oil should be your first option for buying. The lucas oil highviscosity gearoil is made with great service, is incredible and it is highly recommend. Manufacturer says: Browse our exclusive collection of auto accessories that includes top quality products to enhance the style, comfort and functionality of your vehicle. Further, the oil can be bought for good value and it is good for heavy weight.

Most importantly, the lucas oil high viscosity gear oil does the job, is good for good quality and it is made for rear end grease.

Most buyers found that the oil is used for the front axle of the 2007 chevy silverado 4x4 ltz 1500 crew. Moreover, a few also found that the oil works well for an old truck. Also, a few say that the oil will work in the rear differential of your kia. In short, for most buyers, it was what they were looking for.

• This can be used in a 1982 honda express sr gearbox.
• This can be used in front diff in 2005 f250.
• This is perfect for any 8" toyota.
• This is great for heavy-duty applications and it is great for heavy duty.

Best For Transfer Cases: Acdelco High Viscosity Gear Oil

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The Acdelco line of oil comes in a pretty wide variety of styles, so you can definitely find one that suits your individual preferences and needs. The Acdelco high viscosity gear oil worked perfectly and it works well. Acdelco offers a full range of oils, fluids, and vehicle care products to protect, enhance, and maintain your automobile. In addition, it is manufactured to meet expectations for fit, form and function, offering high quality and great value.

Finally, the Acdelco high viscosity gear oil has the best price and it works great.

Almost all buyers agree that the oil will take close to three quarts. And, a few say that the oil will work fine and already has addative for limited slip. Moreover, a few strongly agree that the oil has a friction modifier already in the formula. In short, many have used the oil for more than a few months without letup, and it shows no sign of giving up.

• This is for corvettes & camaro with high performing rearends.
• No need to use a top treat additive.
• The trick is to get the lube thoroughly embedded into the clutch packs.
• This is the gear fluid to use in the rear diff.

Best For Good Value: Ultra 1Plus High Viscosity Gear Oil

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The features department is where Ultra 1Plus High Viscosity Gear Oil truly manages to shine. The ultra 1plus high viscositygear oil is formulated with synthetic base oils and specialty performance additives to provide improved high-temperature thermal and oxidative stability in a wide range of operating conditions. 90 synthetic gear oil, api gl-4 is highly shear stable while also resisting rust, oxidation, foaming, and varnish. And, it maintains film strength for reliable lubrication.

Most importantly, the ultra 1plus highviscosity gear oil is made with fast shipping and it allows for perfect fit.

"90 and it is not leaking and you have done your regular maintenance, you should not have any issues. " - says, one customer. Overall, many customers have used the oil for more than a few months without letup, and it shows no sign of giving up.

• ✅ extended gear and bearing life due to minimal deposits.
• ✅ contribution to reduced maintenance costs and longer equipment life.
• This can buy for good value and it has reduced maintenance costs.

Best For High Temperature: Royal Purple High Viscosity Gear Oil

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If you often find yourself confused about convenient and suitable oil, Royal Purple High Viscosity Gear Oil is your end point. The royal purple high viscosity gearoil is soft and it is of excellent quality. The Manufacturer says: We engineered this ultra-tough, high performance automotive hypoid gear oil to provide maximum protection to heavily loaded gears while maximizing power throughout the drive train. Moreover, this is recommended for use in truck, motor home/rv and automotive front or rear differentials, manual transmissions, and lower gear units of marine engines that specify use of an api gl-5 or gl-4 fluid.

Finally, the royal purple high viscosity gear oil reduces operating temperature plus it is formulated with a friction modifier additive.

Most buyers found that the oil is great for use in the angle drive of the polaris slingshot. Further, they say that the oil can be used in troybilt tiller with good result. Also, they say that the oil is more automotive type of gear lubricant. In short, at the price, they believe that they got a steal of a deal with it.

• Greater wear protection for severe service performance.
• For best performance, follow the manufacturer's recommendations in your vehicle owner’s manual.
• High temperature performance low temperature fluidity.
• This makes gears run smoother, quieter, cooler and longer without overhauls.

Best With Fastest Shipping: Lubrimatic High Viscosity Gear Oil

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Compared with other oils in this category, the Lubrimatic High Viscosity Gear Oil has a convenient design. The lubrimatic high viscosity gear oil is ideal for modern outboard and stern strive lower units. Make sure this fits by entering your model number. Also, the oil is made for stern drive units and it is great for fastest shipping. Finally, the lubrimatic high viscosity gear oil will not void manufacturers ' warranties.

One customer says - "Lower unit lube worked well. ". Most customers found that the oil offers a higher degree of protection but there are extra detergents which could or should be bounced against the mfg.

• meets or exceeds api-mt-1and gl-5 ratings.
• One of the newcomers and featured product.