The transmission feels like slipping because its fluid level is low. However, in rarer cases, it can be an issue with a worn valve body, a faulty solenoid, a worn clutch, or damage to the transmission module itself.
Whether you drive an automatic or a manual, your vehicle's transmission is critical. If the transmission slips or gets stuck in gear, you lose control of your speed and risk stalling out on the road.
When they work correctly, automatic transmissions shift seamlessly with acceleration or deceleration. However, if you're low on fluid, there is wear on the discs, or if there is some other disturbance, your automatic transmission might get stuck in gear, shift gears at the wrong time, or cause your car to die altogether. All in all, you might end up facing an annoying issue: slipping transmission.
Watch out: Some transmission problems require simple solutions like a fluid refill or valve replacement. But, regardless of the problem, it's wise to take action. Manual and automatic transmission slipping can worsen as you drive, causing extra damage to the system or putting unnecessary strain on your engine as it cranks through RPMs without generating power.
You may also notice fluid leaking from the transmission and hear a whining or humming noise.
If your transmission fluid level gets low, it can't correctly pressurize the transmission bands. Then, air bubbles will enter what should be only-fluid parts. While your transmission gears still shift, you'll notice a delay in engagement, which hampers your vehicle's performance.
Your vehicle might get stuck in one gear, or you might smell something burning under the hood.
Your transmission's valve body diverts transmission oil to different clutch pads and bands. It operates sequentially based on engine load and vehicle speed to get you in the right gear. If the valve gets sticky, gears will be triggered incorrectly, and you'll feel like shifting at an inappropriate time.
You may also have difficulty changing gears, switching to reverse, or downshifting.
Clutch packs prevent slipping and wrong gear engagement. The transmission fluid keeps these clean and in the right place. If the fluid breaks down, the discs begin to wear. When the clutch discs get worn, they cannot lock tight enough to avoid slipping, causing the RPMs to flare without transferring torque to the drivetrain.
You may also see your transmission light on or feel your vehicle slip gears.
Transmission solenoids are directed by electricity to push and pull the valves to shift oil pressure correctly to perform various functions. Unfortunately, damages to this part can end up causing your transmission system to lock up and stop slipping when it's supposed to. When this happens, your car stalls out and dies, just like it would if you didn't engage the clutch on a manual transmission.
You may also have difficulty getting your vehicle into gear, or it might not move forward once it's in gear.
The transmission control module is the brain of the transmission. It monitors engine and driver inputs to determine the correct gear. When the inputs stop making sense or if it malfunctions, the module stays in a single gear or "limp mode" so the vehicle can operate in a simplified way to at least drive to a repair shop at a slow speed.
You may smell burning or notice a softness in the clutch pedal.
The clutch pedal is the mechanical connection between the driver and the transmission. It's attached to a flywheel and contains a clutch plate connecting to the transmission's input shaft. When the clutch is engaged, pressure is applied, linking the transmission shaft to the engine. If the clutch disc is worn, it slips, causing the RPMs to rev faster than the speed.
The most common causes for a car’s transmission slipping:
Valve body failing: The valve body is a “box” of channels and passages where transmission fluid passes through to engage valves and gears, ensuring transmission shifts properly. However, the valve body can fail, resulting in gear slipping, as fluid can’t reach certain gears or valves.
Faulty solenoid: The torque solenoid is an electronic component that controls the movement and flow of transmission fluid. This part helps improve fuel efficiency and reduce heat in the transmission system. However, when the solenoid fails, fluid inside the transmission might not work as efficiently, leading to gear slipping.
Failing transmission module: The transmission control module is the transmission’s “brain,” which is where all readings from sensors go so the vehicle can decide when to shift gears properly. However, if the TCM (Transmission Control Module) fails, the vehicle’s gear shifting gets bad, resulting in slipping.
Worn clutch and pack: The clutch is a disc-like component that basically engages and disengages the transmission-engine connection, allowing the driver to shift gears. So, in manual cars, when you press the clutch pedal, you disconnect the engine from the transmission and then shift gears, and then release the pedal. However, the clutch can fail, causing the gear to slip.
Low transmission fluid: Transmission fluid is vital for the transmission system to work, ensuring every internal component that moves inside the system does so without extra friction. However, if transmission fluid is low due to leaks or contamination, the fluid can’t “smooth out” the movement happening when shifting gears, causing slips and tears.
You may also notice fluid leaking from the transmission and hear a whining or humming noise.
If your transmission fluid level gets low, it can't correctly pressurize the transmission bands. Then, air bubbles will enter what should be only-fluid parts. While your transmission gears still shift, you'll notice a delay in engagement, which hampers your vehicle's performance.
These are typical processes and repair services that fix a check engine light issue
The most common reason for a car’s transmission slipping is due to low transmission fluid. The transmission fluid is the lubricant that ensures all transmission components like valves, gears, and pistons can move without suffering too much friction and overheating. The fluid can’t get too low or contaminated, otherwise it’ll stop lubricating effectively, resulting in excessive wear and tear. A common issue seen when transmission fluid is low is that gears can slip since they lack lubrication to control movement properly.
Symptoms it causes: Apart from the slipping gears you might notice stuck transmission, rough idling, grinding noises, lawnmower noises, etc.
High risk of priority: Low transmission fluid quickly leads to further damage to the transmission’s internal components, eventually resulting in major breakdowns. The vehicle might suddenly stop working or responding.
Transmission fluid can get contaminated by transmission components deteriorating and leaving particles; this is often the case of clutch problems in manual transmissions, for example. Additionally, transmission fluid can also escape the system, resulting in a lower volume than necessary; this can happen due to leaks and cracks in fluid pans, hoses, lines, etc.
Go safe: Ask for a mechanic to inspect your vehicle’s transmission system to investigate if the transmission fluid is leaking due to surrounding components and if there’s further damage to check out. Many shops do transparent vehicle inspections and lay out your options after investigating your vehicle’s conditions.
What’s a vehicle inspection? It’s “detective work” on your vehicle, checking its systems to see if anything prevents the car from working as expected. In this case, mechanics examine different parts of your vehicle to track if anything is causing the transmission fluid to leak out or get contaminated. They’ll also check the condition of components during their inspection, noting which are causing the problem and which got affected by it, recommending to replace them in order of priority.
A transmission system inspection is the most transparent process to understand why your vehicle’s transmission fluid is low. This is because many components surrounding the transmission clutch and valve body can have a say in the issue, indicating the real culprits that caused it all.
Let’s read an example of how this kind of inspection helps to service a transmission fluid leak.
A customer dropped off the vehicle after having difficulty getting it into gear when they put it in "drive." They reported that they almost had to accelerate it a bit to engage the gear. They also noticed some fluid leaking under the car and wanted the technician to look at that too.
On the test drive, the technician noted a delay in engagement when they put the transmission into gear. They also noted slight engine flaring when the vehicle was shifting.
During the vehicle health inspection, the technician noted that the transmission fluid was deficient. After raising the vehicle on the lift, they said there was a lot of oil leaking from the transmission pan gasket.
The technician recommended replacing the transmission pan gasket and the filter in the transmission pan. After replacing the transmission pan gasket and filter, the vehicle was topped off and taken for a test drive. The transmission fluid leaks were fixed, thus proving that the low transmission fluid was the cause of the delayed engagement.
In this case, the mechanic put the “Immediate Action” tag on the transmission fluid and pan gasket.
Below are just a few examples of typical Symptoms and Fixes your car might be experiencing