What Color Is Transmission Fluid?

Fresh automatic transmission fluid is typically bright red to pink and translucent; some continuously variable transmission (CVT) fluids are dyed green or blue, and dual‑clutch/manual gearbox fluids are usually amber or honey‑colored. If the fluid is dark brown or black, smells burnt, looks milky, or contains metallic flakes, it signals trouble and service is needed. Here’s how color varies by transmission type, what each shade can mean, and how to check it safely.

Why Transmission Fluid Is Dyed

Automakers and lubricant suppliers dye transmission fluids to help technicians quickly distinguish them from engine oil, coolant, brake fluid, and power-steering fluid. The dye also provides a quick visual cue of oxidation and contamination over time, though color alone isn’t a definitive health check—additives, heat cycles, and fluid formulations vary by brand and model.

Common Transmission Fluid Colors and What They Mean

The list below outlines typical colors you might see across transmission types and what those colors usually indicate about condition and urgency for service.

• Bright red or pink, translucent (ATF): Normal for many conventional automatics; indicates fresh, healthy fluid.
• Light amber to clear (DCT/manual/transaxle oils): Common for dual‑clutch transmissions and many manual gear oils; normal when clean and translucent.
• Green or blue (CVT-specific fluids): Normal for many CVT formulations; manufacturers dye CVT fluids differently to prevent misfills.
• Dark brown (all types): Oxidized/aged fluid; service or replacement is advisable, especially if shift quality has degraded.
• Black with burnt odor: Overheated or severely degraded; risk of clutch/band damage—schedule diagnostic and service promptly.
• Milky, pink/gray, or foamy: Possible coolant or water contamination (e.g., failed transmission cooler); immediate inspection is critical.
• Shiny metallic flakes or glitter: Abnormal internal wear; have the transmission inspected before just replacing fluid.

While color offers useful clues, always pair it with smell (burnt/varnish odors), shift behavior (slipping, shudder), and the maintenance schedule in the owner’s manual to decide next steps.

How to Check Transmission Fluid Color Safely

Modern vehicles vary widely in how transmission fluid is checked. Some have dipsticks; many newer units are “sealed” and require specific temperature and level procedures. Follow the maker’s instructions to avoid misreads or damage.

1. Consult the owner’s manual or service information to confirm the correct procedure, temperature range, and fluid specification. Many late-model transmissions have no dipstick.
2. Warm the vehicle to the specified transmission temperature (often roughly 30–50°C / 86–122°F), with the engine idling and the car on level ground.
3. Engage the parking brake and cycle slowly through all gear positions, pausing briefly in each, then return to Park.
4. If equipped with a dipstick: remove it, wipe clean, reinsert fully, remove again to check level, color, and smell. Dab fluid on a white paper towel to judge clarity.
5. If “sealed”: use the manufacturer’s fill/level plug method at the specified temperature. This may require a scan tool to read transmission temperature. Do not open plugs on a hot transmission without proper safety and leveling.
6. Evaluate: healthy fluid is translucent and within the correct level range; burnt odor, discoloration, or contamination warrants service.

If you’re unsure about the correct procedure or tools, have a qualified technician perform the check—especially on sealed or temperature‑critical systems.

When to Change or Service Transmission Fluid

Change intervals depend on the transmission type, driving conditions, and manufacturer guidance. “Lifetime” fluid claims often assume ideal conditions; severe use shortens intervals.

• Conventional automatics (AT): Commonly 60,000–100,000 miles (100,000–160,000 km) under normal use; 30,000–60,000 miles (48,000–96,000 km) for severe service (towing, city stop‑and‑go, hot climates).
• CVTs: Often benefit from 30,000–60,000‑mile (48,000–96,000 km) intervals under severe use; normal schedules vary widely—check the manual.
• Dual‑clutch (DCT): Typically 40,000–60,000 miles (64,000–96,000 km) for fluid and, where applicable, filter service.
• Manual gearboxes/differentials: Commonly 30,000–60,000 miles for severe use; up to 100,000 miles in normal service, per manufacturer.
• Always use the exact specification: ATF, CVT fluid, and DCT fluid are not interchangeable; using the wrong one can cause damage.

If your fluid is discolored or you notice slipping, shuddering, delayed engagement, or new noises, don’t wait for the scheduled interval—have it inspected.

FAQs

Is red fluid always transmission fluid?

Often, yes—ATF is commonly red—but some power steering systems also use red ATF, and coolant leaks can appear pink. Verify source and smell; ATF feels oily and may have a slightly sweet, varnish‑like odor.

Can I judge fluid health by color alone?

No. Color is a useful indicator, but additive chemistry, heat cycles, and dye variations mean two healthy fluids can look different. Consider smell, shift quality, mileage, and lab analysis (used oil analysis) for certainty.

What if I find a red or green puddle under my car?

Identify the fluid type and source promptly. Transmission fluid leaks can worsen quickly and lead to low fluid levels, causing damage. Look for drips near the transmission pan, cooler lines, or radiator end tanks (if the cooler is integrated).

Summary

Most fresh automatic transmission fluids are bright red/pink and translucent; CVT fluids may be green or blue, and DCT/manual fluids are typically amber. Dark, burnt, milky, or glittery fluid points to degradation or contamination and calls for prompt service. Check color and level using the manufacturer’s procedure and follow the specified fluid type and maintenance intervals for long transmission life.

Does the color of transmission fluid matter?

The color of transmission fluid is a vital diagnostic tool that indicates the condition of the fluid and, by extension, the transmission’s health. Regularly checking the fluid’s color can prevent serious maintenance issues and help maintain vehicle performance.

What color is bad transmission fluid?

Bad transmission fluid appears brown, dark brown, black, milky, or foamy, with the color indicating a problem like overheating, contamination, or oxidation. The only normal colors for transmission fluid are bright red or dark red; any deviation from this, especially a burnt smell or a foamy/milky appearance, signals that the transmission fluid needs immediate inspection and service from a professional mechanic.
 
Normal Colors 

• Bright red: Fresh, clean, and healthy fluid.
• Dark red: New or normal, slightly aged fluid.

Abnormal Colors & What They Mean

• Brown or Dark Brown: The fluid is old, dirty, and oxidizing. 
• Burnt Red or Black: The fluid is burnt and severely oxidized, indicating overheating or internal damage, and needs immediate attention. 
• Milky, Foamy, or Bubbly: Water or coolant has mixed with the transmission fluid, often due to a leak. 
• Cloudy or Muddy: Indicates contamination with debris or other particles. 

When to Seek Professional Help

• Dark Brown or Black: Go to a mechanic immediately, as internal damage may have already occurred. 
• Milky, Foamy, or Cloudy: A professional should inspect the transmission for leaks or contamination. 
• Bright Red with Metal Particles: This could be a sign of significant internal wear and should be diagnosed right away. 

What color is full synthetic transmission fluid?

Healthy transmission fluid typically falls within a range of colors, including bright red, translucent pink, or even light brown. It’s a synthetic fluid that is normally almost clear, and the color is a dye that helps identify the type and condition.

What color is transmission fluid when it leaks?

Transmission fluid that is leaking from a vehicle is usually red, but the shade can vary from dark red to a deeper, rust-red color depending on its age and how much it needs to be changed. Fresh transmission fluid is translucent and dark red, while fluid that needs to be changed can become brownish or even almost black. You can also often identify it by its slick, oily consistency and a petroleum-like odor.
 
This video explains how to distinguish between different types of car fluid leaks: 58sYourMechanicYouTube · May 4, 2016
How to Confirm a Transmission Fluid Leak
In addition to the color, look for these other signs:

• Color: While usually red, the exact shade indicates its condition. 
• Consistency: It will feel slick and oily to the touch, similar to engine oil. 
• Odor: Fresh fluid has a petroleum smell, but burnt transmission fluid will have a distinct burnt odor. 
• Location: Leaks often originate from the middle and front of the vehicle. 

Other Red Leaks
Be aware that red fluid could also be power steering fluid. If you see a leak, it’s important to have it diagnosed by a professional, as it could indicate a problem with the transmission or power steering system.