Are Transmission Fluid and Power Steering Fluid the Same?

[McEli]

Transmission fluid and power steering fluid are not the same. Here are the specific details about these two fluids: 1. Transmission fluid can be added to the power steering pump, but power steering fluid cannot be added to the transmission as it does not meet the required specifications. 2. Power steering fluid is a special liquid used in the car's power steering pump. Through hydraulic action, it makes the steering wheel very light, similar to automatic transmission fluid, brake fluid, and shock absorber fluid. 3. Automatic Transmission Fluid (ATF) is specifically designed for automatic transmissions. Early automatic transmissions did not have dedicated fluid and instead used engine oil as a substitute.

[Curtis]

Last time I helped a friend check out a car, I ran into this exact issue. Transmission fluid and power steering fluid are definitely not the same thing! Transmission fluid is specifically for the gear sets, needing to withstand high pressure and high temperatures; power steering fluid manages the steering wheel's resistance, more like the lifeblood of a hydraulic system. I once saw a rookie at a repair shop mistakenly add power steering fluid to the transmission, and the result was gears shifting like a tractor. Nowadays, new car manuals label everything clearly, but even seasoned drivers should store them in separate bottles—don’t cut corners and mix them up. If you really can’t tell, just take a whiff—transmission fluid has a sulfur-like smell, while power steering fluid doesn’t have any distinct odor.

[OAlejandro]

Running an auto repair shop for twenty years, these are the questions customers ask most frequently. Simply put, transmission fluid serves the gearshift mechanism and needs to be as smooth as honey; power steering fluid is all about the steering wheel's weight and responsiveness, requiring it to flow as sensitively as mercury. Just the other day, a car owner poured gear oil into the power steering reservoir, resulting in the steering gear squeaking like a rusty door hinge. Nowadays, car manufacturers are even more meticulous: Volkswagen uses light green G004000 for power steering fluid but bright red G055025 for transmission fluid, clearly indicating they shouldn't be mixed. Honestly, checking the symbols on the reservoir cap is the easiest way—the steering wheel icon and the gear icon are worlds apart!

[LaHailey]

These are two entirely different things. Transmission fluid is primarily responsible for lubricating the planetary gear sets and clutch plates, and must maintain viscosity stability under high temperatures; power steering fluid, on the other hand, serves as a medium for transmitting hydraulic pressure, requiring extremely high fluidity. My old Mercedes S500 suffered because of this—back then, I took the easy route and mixed them, which led to the power steering pump whining and cost me 3,000 to replace it. Remember this rhyme: red oil for transmission (most ATF is red), clear oil for steering (PSF is usually transparent). New car owners should just check Chapter 7 of the manual—don’t believe those all-in-one oil ads.

[VanHarley]

Hah, I actually handled this issue at a tuning shop last month. Transmission fluid is usually in the black reservoir on the left side of the engine, designed to withstand 200°C temperatures; the power steering fluid reservoir is on the right with a steering wheel icon, operating at around 80°C. Once when changing fluid for a Civic, I discovered using the wrong fluid can corrode rubber seals. My tuning circle friends now use electronic tags to differentiate: DEXRON-VI for the gearshift symbol, CHF-11S for the steering wheel symbol. Regular owners just need to remember: deep red fluid is typically for the transmission system, while clear pale yellow is usually for power steering. During maintenance, keep an eye on the mechanic to avoid mixing up the containers!