Motul Gear 300 vs Gear 300 LS: Which for Track & LSD?

Motul Gear 300 vs Gear 300 LS is the gearbox-and-diff question that shows up right after you settle engine oil. Round 3 covered Motul 300V for the engine. This post stays on transmission and axle fluid—where the wrong bottle can chatter an LSD, wear syncros, or leave a hypoid gear under-protected on a hot weekend.

Both Gear 300 and Gear 300 LS are Motul ESTER Core® 75W-90 racing lubricants with API GL-4 / GL-5 language on the current technical data sheets. The difference that matters is limited-slip friction modification. Gear 300 is Motul's pick for gearboxes and hypoid diffs without limited-slip systems. Gear 300 LS adds a dedicated friction modifier for clutch-type LSDs. This guide sticks to Motul's TDS wording, explains where Gear Competition 75W-140 and Motul 90 PA sit, and keeps DCT fluid out of the wrong fill.

Gearbox Oil vs Differential Oil

A manual gearbox and a differential can share a housing (transaxle) or live in separate cases. Either way, the fluid has to:

• Protect gears under shock load and high temperature
• Let synchronizers (or dog rings) do their job
• Match clutch-pack friction in a limited-slip differential when one is present

Put a non-LS gear oil in a clutch-type LSD that needs friction modification and you can get chatter, grab or poor lockup. Put a heavily friction-modified LS oil where Motul or the OEM says not to, and you can upset syncro feel or electronic LSD behavior. Motul's TDS sheets draw that line clearly—follow them, not a forum "I run X in everything" post.

DCT and DSG cars are a separate story. They need dual-clutch fluid (Motul High Performance DCT Fluid or Multi DCTF where specified), not Gear 300. See Do You Need a DCT Cooler for Track Days? for the cooler side of that world.

Motul Gear 300 75W-90: What Motul Publishes

Motul's Gear 300 75W-90 TDS (ESTER Core®) describes a racing lubricant for gearbox and differential use. Type-of-use language includes track, speedway, rally and rally raid. Motul lists it for:

• Mechanical transmissions, synchronized or non-synchronized gearboxes
• Gearboxes/differentials, transfer gearboxes
• Hypoid differentials without limited-slip systems
• High-performance gearboxes and transmissions without limited-slip systems in racing and street conditions

Performance highlights from the TDS:

• High-performance synthetic ESTER Core® with Extreme Pressure (EP) additives
• API GL-4 / GL-5, "above existing standards"
• Viscosity grade 90 at high temperature for film strength and noise control
• 0% shear loss language; stays in viscosity grade 90 after KRL 20-hour shear test (SAE J306)
• Fluid at low temperatures for easier cold shifting
• Suitable for seals and yellow metals used in gearbox design
• Oil change: according to manufacturers' requirements; adjust according to your own use

Selected Gear 300 75W-90 properties (Motul TDS): density 0.856 @ 20°C; viscosity 87.7 mm²/s @ 40°C and 14.4 mm²/s @ 100°C; VI 171; pour point −51°C / −60°F; flash point 206°C / 403°F.

Motul Gear 300 LS: Limited-Slip Friction Modification

Gear 300 LS 75W-90 keeps the same ESTER Core® / EP story and adds the LS-specific claim Motul prints on the sheet: "Included dedicated friction modifier to increase limited slip differential efficiency, and avoid noisy or dragging limited slip differential."

Motul's type-of-use list for Gear 300 LS includes:

• Track, speedway, rally, rally raid, and electric-vehicle transmissions (Motul's wording)
• All hypoid differentials with limited-slip systems
• Gearboxes with integrated limited-slip differentials
• Mechanical transmissions, synchronized or non-synchronized gearboxes, transfer gearboxes under shock and heavy load
• High-performance gearboxes and transmissions in racing and street conditions

Selected Gear 300 LS 75W-90 properties (Motul TDS): color green; density 0.859 @ 20°C; viscosity 102.2 mm²/s @ 40°C and 16.3 mm²/s @ 100°C; VI 173; pour point −45°C / −49°F; flash point 218°C / 424°F. Standards: API GL-4 / GL-5, above existing standards. Oil change: according to manufacturers' requirements; adjust to your own use.

If your LSD is electronically controlled and the OEM forbids aftermarket LS additives, the owner's manual wins—even if Gear 300 LS looks like the "track" bottle.

Side-by-Side Plus Gear Competition and 90 PA

Naming note on TRP: our catalog lists Motul "GEAR FF COMP 75W140." Motul's current product and TDS name for that 75W-140 ester LS gear oil is Gear Competition 75W-140 (Motul ref 105779). Same viscosity family and LS friction-modifier story—confirm the bottle label matches the Motul TDS before fill.

Motul 90 PA remains the older mineral Extreme Pressure LSD lubricant Motul describes for limited-slip differentials in racing cars, 4WD, passenger cars and work vehicles. Motul notes that for BMW rear axles with limited-slip differentials you should use Motul Hypo Synt LS 75W-140 or Motul Gear Competition 75W-140 instead of 90 PA. Useful context compound; not the default modern track fill when Gear 300 LS or Gear Competition matches the application.

Manual Trans vs Open Diff vs Clutch LSD vs Electronic LSD

Match the bottle to the hardware:

1. Manual gearbox, open differential (or non-LS hypoid): Motul Gear 300 per the non-LS type-of-use list.
2. Clutch-type LSD (standalone or integrated) that needs LS additive: Motul Gear 300 LS when Motul lists it for that duty; Gear Competition 75W-140 when a 140-grade LS oil is specified or Motul's thicker LS ester is the better match.
3. Transaxle sharing gearbox + LSD: follow Motul's integrated-LSD language (Gear 300 LS / Gear Competition) and any OEM capacity/spec notes—one wrong fluid affects both functions.
4. Electronically controlled LSD / torque-vectoring axle: owner's manual and OEM fluid first. Do not assume a friction-modified aftermarket gear oil is allowed.
5. DCT / DSG: Motul DCT fluids only—not Gear 300 or 300 LS, regardless of any "DSG" wording that appears in a store title string.

Change Intervals After Track Heat

Motul will not publish a universal "change every two track weekends" rule on these TDS sheets, and neither will we invent one. Motul's line is: according to manufacturers' requirements and adjust according to your own use.

Practical track process:

1. Fresh fill before a hard weekend if the fluid already has a season of heat.
2. Inspect color, smell and level after the first hot event on a new fill.
3. Shorten the interval when temps run high, when you hear new LSD chatter, or when fluid smells burnt.
4. Lengthen only with evidence—not optimism.
5. Never top off a Motul ester fill with a random mineral gear oil if you are trying to keep the Motul chemistry intact.

Engine oil change habits from the Motul 300V track oil guide do not automatically transfer to gear oil volumes—gearboxes and diffs often hold less fluid and see different shear and heat.

Which Bottle for Your Car

Common Questions

Gear 300 or Gear 300 LS—which do I need?

If the differential has no limited-slip clutch pack (open or non-LS hypoid) and Motul's non-LS Gear 300 list matches, use Gear 300. If you have a clutch-type LSD that needs friction modification, Motul's Gear 300 LS is the 75W-90 ester bottle with the dedicated friction modifier. Confirm on Motul's chart and your owner's manual.

Can I use Gear 300 in an LSD?

Motul positions Gear 300 for hypoid differentials without limited-slip systems. A clutch-type LSD that needs LS additive is the Gear 300 LS (or Gear Competition 75W-140) path. Using the non-LS oil in an LSD that needs friction modification is how chatter and grab show up.

Motul Gear 300 vs Red Line?

Both brands sell high-performance gear oils; this post stays on Motul TDS numbers we have on hand. Compare Red Line's published TDS for the exact viscosity and LS/non-LS product against Motul's sheets and your OEM spec—do not treat "track brand" as a substitute for GL rating and LS friction needs.

How often should I change diff fluid after track days?

Motul says follow the manufacturer and adjust to your use. Hot HPDE weekends usually mean shorter intervals than street bumper-sticker schedules. Inspect fluid after hard events; change sooner if it smells burnt or the LSD behavior changes.

Is Motul 90 PA still relevant?

Yes as a Motul EP mineral LSD lubricant still published and stocked, especially for older or Motul-specified LS axles. For many modern BMW LS rear axles Motul itself points to Hypo Synt LS 75W-140 or Gear Competition 75W-140 instead. Read the application, not nostalgia.

Can I put Gear 300 in a DCT?

No. DCT / DSG units need dual-clutch fluid (Motul High Performance DCT Fluid or Multi DCTF where specified). Gear 300 and Gear 300 LS are hypoid/gearbox gear oils. Ignore any store-title "DSG" wording that conflicts with Motul's TDS.