Symptoms of Low Transmission Fluid

Transmission fluid plays a crucial role in the operation of your transmission. While we often think of the gearbox itself when talking about transmission maintenance, keeping your transmission fluid fresh will help prolong its life and keep your vehicle shifting smoothly. The hydraulic and lubricating properties of transmission fluid are important. When your transmission fluid is low, you may notice a change in how your car shifts, and may even cause damage to the internal workings of the gearbox.

What is Transmission Fluid?

Transmission fluid is the hydraulic fluid contained within your gearbox that provides lubricative, hydraulic, and cooling properties. It carries out a few essential responsibilities for your vehicle’s transmission. 

One of the most important responsibilities for transmission fluid is the lubrication of the gears themselves, ensuring the proper amount of friction for smooth shifts and mitigating harmful internal wear as much as possible. 

Transmission pan spilling fluid

The fluid also has hydraulic properties, allowing force to be transferred through the fluid within the gearbox, which is essential for gear changes. 

Another important duty of transmission fluid is cooling, as it conducts heat from the gearbox. In most automatic transmission vehicles, the hot fluid is sent to a transmission cooler for heat to be dissipated and then returned to the transmission. In manual transmissions, these coolers aren’t generally needed as manual transmissions don’t produce the amount of heat that automatics do. 

Automatic vs. Manual Transmission Fluid

Although they have many of the same properties and responsibilities, there are still some important differences between automatic transmission fluid (ATF) and manual transmission fluid you should know. 

ATF is generally less viscous than its manual counterpart and provides lower friction to allow the complex internals of automatic gearboxes to operate smoothly. 

Manual transmission gear oil on the other hand is thicker and has higher friction properties, which is necessary for the precise switching of gears. These varying friction properties and chemical makeups are why it’s so crucial to use the proper type of fluid for your transmission. 

Manual shifter knob

Symptoms of Low Transmission Fluid

Although the issues caused by low fluid can vary depending on a host of factors, there are some common ones to keep your eyes out for as a vehicle owner. 

Strange Noises

When the fluid within your transmission has either reached a dangerously low level or has been burnt and contaminated, it can reduce the lubricating properties of the fluid and cause the transmission to make noises it normally doesn’t.

These noises can range from metallic grinding and clunking in manuals to high-pitched whining or whirring in automatics. 

Unfortunately, you can’t just rely on your ears to judge the health of your transmission fluid. Instead, you should have your vehicle inspected by a trusted automotive professional if you encounter any strange noises. 

Slipping Gears

One of the telltale signs of low or contaminated transmission fluid is the feeling of gears “slipping” while driving.
It’s a hard sensation to explain, but you may feel the gears slip out of the intended gear when attempting to shift. You may feel your engine rev high and disengaged (as if your gearbox is in neutral). This is often accompanied by a “jerking” feeling as the vehicle lurches forward after a slipped gear. 

Transmission slipping is not something to ignore, as it can lead to abrupt unintended shifts that leave you in dangerous driving circumstances and even pose a risk to the components of the transmission itself. 

Visible Leaks

Of course, one of the most obvious signs of low transmission fluid is a leak. You may see red fluid leaking from the transmission pan itself or in a puddle on your driveway. 

As stated before, transmission fluid is your gearbox’s source of lubrication, cooling, and shifting function,  so visible loss of fluid is something you should address as soon as possible to avoid potentially expensive repairs or irreparable damage.

Slow or Harsh Shifts

Since transmission fluid provides hydraulic pressure to allow for quick shifts, the lack of this fluid can cause your transmission to have trouble making smooth gear engagements.

This delayed engagement can make your vehicle buck forward during acceleration or deceleration (similar to a slipping transmission) and lead to an unpleasant driving experience. 

Transmission Service at Scott’s U-Save

Whether you drive an automatic or a manual, the highly-trained transmission technicians at Scott’s U-Save have the expertise and equipment to service your vehicle with the highest quality possible. Give us a call or schedule an appointment online today.

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