Transmission Slipping
Hearing that your transmission is slipping can be incredibly worrying, but take a deep breath. This is a common issue, and in many cases, it's understandable and fixable. We'll help you figure out what's going on and what steps to take next.
Transmission slipping is a relatively common issue, especially in vehicles with higher mileage or those that haven't had regular transmission maintenance.
Can I drive my car right now?
Limit driving, seek inspection
Driving with a slipping transmission can quickly worsen the problem, potentially leading to complete transmission failure and leaving you stranded. It's best to limit driving to short distances if absolutely necessary, and get it inspected as soon as possible.
Transmission slipping is most commonly caused by low or contaminated transmission fluid, which prevents the transmission from building proper hydraulic pressure. Other frequent causes include worn internal components like clutch packs or a faulty torque converter. Addressing fluid issues often resolves the problem, but internal wear typically requires professional repair.
What You'll Notice
- 1Engine RPMs rise sharply without a corresponding increase in vehicle speed
- 2Vehicle feels sluggish or slow to accelerate, especially from a stop
- 3Difficulty shifting gears, or gears 'hunting' erratically
- 4A noticeable delay or 'lag' when shifting from Park to Drive or Reverse
- 5Burning smell, especially if fluid is low or overheating
Most Likely Causes
Ranked by probabilityLow or Contaminated Transmission Fluid
Transmission fluid is the lifeblood of your automatic transmission, providing hydraulic pressure for shifting, lubrication, and cooling. If the fluid level is too low, or if it's old and contaminated (dark, burnt smell), the transmission can't build the necessary pressure to engage gears properly, leading to slipping. Checking and correcting the fluid level, along with a fluid and filter change, resolves the issue in about 9 out of 10 cases where this is the root cause.
Worn Clutch Packs or Bands (Internal Wear)
Inside your transmission are friction materials, like clutch packs and bands, that engage and disengage to select gears. Over time and mileage, these materials wear down, losing their ability to grip. When they can't grip effectively, the transmission slips. This is a significant internal mechanical failure and typically requires a transmission rebuild or replacement to resolve.
Faulty Torque Converter
The torque converter acts like a fluid coupling between the engine and transmission, allowing the engine to spin while the vehicle is stopped in gear. If the torque converter's internal components (like the stator or clutch) fail, it won't efficiently transfer power, leading to a feeling of slipping, especially under acceleration or when the lock-up clutch should engage. Replacing the torque converter typically resolves this specific issue.
Faulty Shift Solenoids or Valve Body
Shift solenoids are electronic valves within the transmission's valve body that direct fluid to engage specific gears. If a solenoid becomes clogged, sticks, or fails electrically, it can prevent proper gear engagement or cause delayed, harsh, or slipping shifts. A faulty valve body itself can also cause these issues. Replacing the faulty solenoid(s) or the entire valve body (depending on the diagnosis) typically resolves the problem.
Transmission Control Module (TCM) or Sensor Failure
The TCM is the 'brain' of your automatic transmission, using data from various sensors (like vehicle speed sensors, input/output speed sensors, throttle position sensor) to determine when and how to shift. If the TCM itself fails, or if it receives incorrect data from a faulty sensor, it can command improper shifts or cause slipping. Diagnosing these electronic issues requires specialized tools and expertise. Replacing the faulty sensor or TCM (after proper programming) typically resolves the issue.
Don't Confuse With
Engine Misfire or Fuel System Issue
An engine misfire or fuel delivery problem can cause the engine to 'bog down' or lose power, which might feel like the transmission is slipping. However, with an engine issue, the RPMs typically won't surge without speed gain, and you might notice rough idling or a check engine light for misfire codes (P030X). Transmission slipping specifically involves the engine revving but the car not accelerating as it should.
Clutch Slipping (Manual Transmission)
While the symptom is similar, an automatic transmission doesn't have a driver-operated clutch pedal. If you have a manual transmission, a 'slipping clutch' is a distinct issue where the clutch disc itself is worn. For automatics, the 'slipping' refers to internal components or fluid pressure issues.
How to Diagnose
- 1**Check Transmission Fluid Level & Condition:** This is the first and easiest step. With the engine warm and running (and the vehicle on level ground), check the dipstick (if equipped) according to your owner's manual. Note the fluid color (should be red/pink, not dark brown or black) and smell (should not smell burnt).
- 2**Inspect for Leaks:** Look under the vehicle for any red or brown fluid puddles or wet spots around the transmission pan, lines, and seals.
- 3**Scan for Trouble Codes:** Use an OBD-II scanner to check for any stored or pending transmission-related codes (P07XX series). Even if the Check Engine Light isn't on, there might be codes stored.
- 4**Observe Driving Symptoms:** Pay close attention to when the slipping occurs – under light acceleration, hard acceleration, specific gears, or when shifting from Park/Neutral to Drive/Reverse. This information is crucial for diagnosis.
- 5**Professional Inspection:** If fluid levels are correct and healthy, or if you find significant leaks, a professional mechanic with specialized diagnostic tools (like a pressure gauge and advanced scan tool) will be needed to pinpoint internal issues.
Related OBD Codes
These codes are typically related to the transmission control system. P0700 is a general transmission control system malfunction code, often indicating that the Transmission Control Module (TCM) has detected a fault and turned on the Check Engine Light. Other codes like P073X series indicate incorrect gear ratios, suggesting internal slipping. P074X codes point to torque converter clutch issues, and P075X codes relate to shift solenoid malfunctions. Sensor codes like P0715 or P0720 indicate problems with speed sensors.
When to Call a Professional
- If your transmission fluid is at the correct level and appears healthy, but the slipping persists, indicating internal damage.
- If you find significant fluid leaks that are beyond a simple pan gasket replacement.
- If your vehicle requires specialized diagnostic tools (like a factory scan tool for solenoid testing or pressure gauges) that you don't have.
- If you're not comfortable working under the vehicle or dealing with transmission fluid. If you're not comfortable working on complex internal transmission issues, that's a smart decision – this is exactly what mechanics specialize in.
What to Tell Your Mechanic
To help your mechanic accurately diagnose the problem and provide a fair quote, be as detailed as possible about when and how the slipping occurs.
• When does the slipping occur (e.g., cold, hot, specific gears, under acceleration)?
• What does it feel like (e.g., engine revs, delayed engagement, harsh shift)?
• Have you noticed any fluid leaks or smells?
• Has the Check Engine Light come on?
Frequently Asked Questions
What does transmission slipping feel like?
It often feels like the engine revs up but the car doesn't accelerate as it should, or there's a delay or 'lurch' when shifting gears. You might also notice a loss of power, especially when starting from a stop or accelerating uphill.
Is it safe to drive with a slipping transmission?
No, it's generally not safe to drive with a slipping transmission. It can lead to further, more severe damage to the transmission, potentially causing complete failure and leaving you stranded. It also compromises your vehicle's ability to accelerate and maintain speed, which can be dangerous in traffic.
How often should I change my transmission fluid?
This varies greatly by vehicle and manufacturer. Some recommend every 30,000-60,000 miles, while others claim 'lifetime' fluid (though most technicians recommend changing it around 100,000 miles even then). Consult your owner's manual for your specific vehicle's maintenance schedule.
Can low transmission fluid cause slipping?
Yes, absolutely. Low transmission fluid is one of the most common causes of slipping. The transmission relies on hydraulic pressure from the fluid to engage gears, and insufficient fluid means insufficient pressure.
What's the difference between a transmission rebuild and replacement?
A rebuild involves disassembling your existing transmission, replacing worn components (like clutch packs, seals, gaskets), and reassembling it. A replacement involves installing a new or remanufactured transmission unit into your vehicle. Rebuilds can sometimes be more cost-effective if the main case is sound, while replacements offer a fresh start.
How do I know I'm ordering the right part?
At Auto Barn, we make it easy. Simply enter your vehicle's year, make, and model on our website, and we'll show you parts guaranteed to fit. If you have any doubts, our customer service team is ready to help verify fitment before you order.
Related Symptoms
Repair Cost Estimate
DIY (Quality Parts)
50-70k miles
$50-$120
Shop Repair
Parts + labor
$200-$450
Save $150-$350 by DIYing a transmission fluid and filter change.
Difficulty
intermediate
Time
1-2 hours
Parts You'll Need
Automatic Transmission Fluid (ATF)
The most common cause of slipping is low or old, contaminated fluid. Replacing with the correct type of fresh fluid often resolves the issue by restoring proper hydraulic pressure and lubrication. This resolves the issue in about 9 out of 10 cases where fluid is the primary problem.
Check your owner's manual for the exact fluid type and capacity (typically 4-12 quarts for a drain and fill, more for a full flush).
Transmission Filter Kit
A clogged transmission filter restricts fluid flow, contributing to low pressure and slipping. Replacing the filter along with the fluid ensures optimal fluid circulation and removes contaminants. This is a critical component of a successful fluid service.
Typically one filter per service. Kits usually include a new pan gasket.
Transmission Pan Gasket
A new pan gasket is essential when dropping the transmission pan to change the filter and fluid. It ensures a leak-free seal, preventing fluid loss that could lead to future slipping.
Typically included with a transmission filter kit, but available separately if needed.
Tools You'll Need
- Socket set and ratchet
- Torque wrench
- Drain pan (large capacity)
- Funnel
- Fluid pump (if no dipstick tube)
- Jack and jack stands
- Gasket scraper or plastic razor blade
Safety Gear
- Safety glasses
- Nitrile gloves
- Creeper (optional, but helpful)
- Family-owned since 1957
- 990,000+ happy customers
- Fast nationwide shipping
- 30-day hassle-free returns
Guaranteed to fit or we'll make it right
Car problems always seem to happen at the worst time, and transmission issues can feel especially daunting. We're here to provide clear, actionable information to help you navigate this challenge.
Every car is different, and we want you to stay safe. If anything feels off during your inspection, or you're unsure about what you're seeing, a professional inspection is always a smart call. For brakes, steering, and suspension, we especially recommend having a mechanic verify before driving.