Red Line MTLV 70W75 GL-4 Gear Oil - Quart - 50604

The Red Line MT-LV 70W/75W GL-4 Gear Oil (Part #50604) is a full-synthetic, ester-based manual transmission fluid engineered for drivers who demand more than what a conventional or OEM gear oil can deliver. Sold here in a convenient one-quart bottle, this lubricant is designed specifically for manual transmissions and front-wheel-drive transaxles — including dual-clutch applications — where precise synchronizer friction characteristics and robust gear protection are non-negotiable.

Key Features & Benefits

• Full-Synthetic Ester-Based Formula: Red Line builds MT-LV on a full-synthetic ester base, which delivers superior film strength and thermal stability compared to conventional petroleum-based gear oils — keeping your transmission protected under hard use and temperature extremes.
• Safe for Brass Synchronizers: Unlike GL-5 gear oils, MT-LV is formulated without the reactive sulfur compounds that are known to corrode and damage brass synchros. This makes it a go-to choice for transmissions that specify GL-4 or synchromesh fluids.
• Quicker, Smoother Shifts: Red Line engineers MT-LV to deliver a perfect synchronizer coefficient of friction, which translates to noticeably crisper, more precise gear engagement — especially noticeable when rowing through the gears quickly on a spirited drive or at the track.
• Eliminates Notchy Cold Shifting: The low-viscosity 70W/75W rating means this oil flows quickly at cold start, reducing the stiff, notchy feel many manual transmission owners experience on cold mornings before the fluid warms up.
• Dual-Clutch Compatible: MT-LV is explicitly suitable for dual-clutch transmission (DCT) applications that require a GL-4 rated gear oil — broadening its compatibility well beyond traditional H-pattern gearboxes.
• Low Fluid Friction for Better Power Transfer: Reduced internal fluid friction means less parasitic loss through the gearbox, helping more of your engine's power reach the drivetrain.
• Longer Synchronizer Life: High-performance gear protection chemistry helps synchronizers last longer, reducing the likelihood of costly transmission rebuilds from premature synchro wear.
• Broad Service Class Coverage: Meets and is recommended for GL-1, GL-3, and GL-4 applications, as well as most special synchromesh fluid specifications — reducing the guesswork when shopping for the right fluid.

Specifications

• Part Number: 50604
• Brand: Red Line Synthetic Oil
• Viscosity Grade: 70W/75W (satisfies both 70W and 75W viscosity requirements)
• Service Classification: GL-4
• Base Oil Type: Full-synthetic ester-based
• Container Size: 1 Quart (32 fl oz)
• Application Type: Manual transmissions, front-wheel-drive transaxles, dual-clutch transmissions requiring GL-4

Fitment

Red Line MT-LV 70W/75W GL-4 is a universal manual transmission fluid — it is not vehicle-specific in the traditional sense, but it is appropriate wherever the OEM or service manual calls for a GL-4 gear oil, a 70W or 75W viscosity, or a special synchromesh fluid. It is also recommended for GL-1 and GL-3 applications. Common applications include a wide range of manual-transmission-equipped passenger cars, sport compacts, and performance vehicles, as well as FWD transaxles and DCT-equipped platforms that specify GL-4 lubricants.

Important: MT-LV is not a GL-5 fluid. Do not use it in rear differentials or other applications that specifically require GL-5. Conversely, if your transmission requires GL-4 to protect brass synchronizers, a GL-5 differential oil should not be substituted — this is precisely the use case MT-LV is designed to solve. Always cross-reference your owner's manual or OEM service documentation for the specific fluid specification before filling.

What's in the Box

• 1 x Red Line MT-LV 70W/75W GL-4 Gear Oil — 1 Quart Bottle (Part #50604)

Why Buy from ThreePiece.us

At ThreePiece.us, we stock Red Line fluids because we believe in equipping enthusiasts with the same caliber of lubricants used in professional motorsports — not just whatever's cheapest on the shelf. When you order Red Line MT-LV 70W/75W GL-4 from us, you get:

• Free Shipping on Every Order — No minimum, no surprises at checkout.
• Affirm Financing Available — Split your purchase into manageable payments, even on fluid and maintenance orders.
• Expert Support — Not sure if MT-LV is the right fluid for your specific transmission? Our team is here to help you cross-reference your OEM spec before you buy.

Frequently Asked Questions

Q: What is the difference between Red Line MT-LV and a standard GL-5 gear oil?
A: GL-5 gear oils are formulated primarily for hypoid rear differentials and contain reactive sulfur-based extreme-pressure additives. Those same additives can chemically attack and degrade brass synchronizers commonly found in manual transmissions. Red Line MT-LV is a GL-4 fluid that omits those reactive sulfurs, making it safe for brass synchros while still delivering high-performance gear and bearing protection. If your manual transmission or transaxle specifies GL-4, you should not substitute a GL-5 product.

Q: Can I use Red Line MT-LV in a dual-clutch transmission (DCT)?
A: Yes. Red Line explicitly states that MT-LV is suitable for dual-clutch applications that require GL-4 gear oils. As always, verify your DCT's specific OEM fluid specification to confirm GL-4 compatibility before filling.

Q: How much fluid will I need for a complete transmission service?
A: Transmission capacity varies significantly by vehicle and gearbox design. One quart (this listing) may be sufficient for a top-off, but a full drain-and-fill typically requires more. Check your vehicle's service manual for the exact fill capacity and purchase accordingly. Red Line MT-LV is also available in a gallon size if your application requires a larger volume.

Q: Does this fluid replace special synchromesh fluids specified by OEMs?
A: Red Line states that MT-LV is recommended where most special synchromesh fluids are specified, in addition to standard GL-1, GL-3, and GL-4 applications. However, OEM fluid requirements can vary by manufacturer and model year, so we always recommend confirming compatibility against your owner's manual or OEM technical documentation before making the switch.