Why does transmission fluid degrade so quickly when driving in urban areas?

If you frequently get stuck in traffic, stop and go constantly, drive uphill in apartment building parking garages, and park multiple times a day, then your transmission fluid is working harder than you think.

1. Frequent stop-and-go driving increases the temperature of the transmission.

In urban conditions, vehicles must:

- Run slowly
- Stopping at red lights repeatedly
- Inching forward in traffic jams.
- With automatic transmissions (AT, CVT, DCT), every time the car moves forward, the clutch and hydraulic system engage. The continuously increasing friction causes the transmission fluid temperature to rise.

Unlike highway driving – where the vehicle operates steadily at a constant speed – city driving requires the oil to cool and lubricate under constantly fluctuating temperatures.

Prolonged high temperatures will:

- Make the oil oxidize faster.
- Reduce viscosity
- Degradation of anti-wear additives
This is the leading cause of premature transmission fluid degradation.

2. Low load but high friction pressure

Many people think: "When driving slowly in the city, the gearbox is smoother."
The reality is quite the opposite.

At low speeds, especially when the car is moving very slowly, the clutch in the transmission has to slip more.This sliding process produces:

- Local temperature
- Micro-abrasion
- Small metal deposits
- These abrasive particles mix into the oil, causing it to become dirty more quickly and affecting its hydraulic power transmission capabilities.

If the oil is of poor quality or has degraded, the following symptoms may occur:

- Delayed gear shifting
- Slight jerk when shifting gears
- The car is sluggish even though the engine revs up.

3. Traffic congestion makes the cooling system less efficient.

When the car is moving steadily on the highway, the airflow helps the cooling system work more efficiently.

But in crowded cities, cars often:

- Run slowly
- There is no natural airflow.
- The cooling fan operates continuously.

This causes the transmission fluid to remain at a high temperature for longer than normal. Fluid that is "cooked" at high temperatures for an extended period will:

- Reduced lubrication
- Increased risk of foaming.
- Reduced molecular stability

With low-quality transmission fluid, degradation can occur 30–40% faster than under ideal conditions.

4. Do city cars require different oil change cycles?

Not all cars should have their oil changed at the same mileage intervals.

If the car is mainly driven within the city, frequently:

- Traffic jams during rush hour
- Climb the ramp to the parking garage.
- Running technology services
Therefore, the transmission fluid change interval should be shortened compared to the standard recommendation.

Changing the oil at the right time helps:

- Keep the gear shifting smooth.
- Reduce fuel consumption.
- Extends the lifespan of the valve body and clutch assembly.

Solution: Choose high-quality transmission fluid suitable for urban conditions.

High-quality transmission fluid requires:

- Good thermal stability
- High antioxidant capacity
- Strong anti-wear additives
- Precise foam control and force transmission capabilities.
Gartz develops a full range of specialized transmission fluids:

- AT: G4, G6, 6HP, 7G, 9G-HP
- CVT: CVT RED, CVT GOLD
- MT: 75W85
- DCT: DSG, DCTF

Each product is optimally designed for specific gearbox configurations, particularly suited to urban operating conditions in Vietnam.

Conclude

Driving in the city isn't as "gentle" as many people think. The constant stop-and-go traffic, high temperatures, and significant sliding friction are the main reasons why transmission fluid degrades quickly.

Understanding this correctly will help you proactively change the oil sooner when needed and choose high-quality transmission fluid to protect your transmission in the long run.

Gartz – Quality builds the brand. Partnering with you for the durability and performance of your gearbox.