Having your car’s transmission go out while you’re driving is a frightening experience. Your car will suddenly lose power, making it difficult or impossible to accelerate. This leaves you stranded until you can get help. Understanding what causes transmission failure and what to do when it happens can help you handle this emergency safely.
What causes a transmission to fail?
There are several potential causes for a transmission failing while driving:
- Low transmission fluid – Transmissions require a specific amount of transmission fluid to operate properly. If the fluid is low, it can cause the transmission to overheat and fail.
- Leaking fluid – Transmission fluid leaks can cause low fluid levels leading to failure. The source of the leak needs to be repaired.
- Faulty solenoid – Electrical solenoids control gear shifting. If one fails, the transmission may not shift properly leading to failure.
- Worn clutch – The clutch discs that engage gears can wear out over time causing slipping and failure.
- Failed gears – Broken or worn gears inside the transmission will prevent proper operation.
- Electrical issues – Electrical problems can disrupt the computer control of the transmission.
- Overheating – Heat is the #1 enemy of transmissions. Allowing the transmission to overheat from low fluid levels or excessive load can lead to failure.
Transmission failure can also occur due to normal wear and tear over the life of the vehicle. Problems are often preceded by warning signs before complete failure happens.
What are the signs of impending transmission failure?
Watch for these warning signs that may indicate impending transmission failure:
- Difficult or delayed shifting – Transmission hesitates or takes too long to go into gear.
- Gear slipping – Engine revs but car doesn’t accelerate as quickly as normal in a specific gear.
- Burning smell – Burnt transmission fluid smell indicates overheating issues.
- Vibration or shaking – Problems inside the transmission cause abnormal vibrations.
- Noise – Unusual grinding, clunking or whining noises point to internal issues.
- Check engine light – The computer detects a problem and turns on the check engine light.
- Leaking fluid – Look under the car for red or brown spots indicating a fluid leak.
If you notice any of these warning signs, have your transmission inspected and repaired by a professional right away to prevent complete failure.
What happens when your transmission fails while driving?
When the transmission fails completely while driving, several things may occur:
- Loss of power – The car will suddenly feel like it’s lost all power and won’t accelerate.
- Coasting – With no transmission power, the car will roll in the direction it was heading relying solely on momentum.
- Gear slipping – Any remaining gears may slip, causing revving but lack of power to wheels.
- Hard shifting – If gears remain, they may have difficulty or harshly engaging.
- No shifting – The transmission may totally lose the ability to shift gears.
- Warning lights/messages – The check engine light, transmission warning light or error messages may illuminate.
This loss of power makes it difficult or impossible to accelerate the vehicle. At best, you may be able to limp along or coast temporarily before the transmission fails completely. But you will not be able to drive normally or maintain higher speeds. You’ll need to pull over as soon as safely possible before you lose all momentum.
What should you do if your transmission fails while driving?
If you notice the signs of transmission failure, stay calm but act quickly to maintain safety. Here’s what to do:
- Pull over – Carefully maneuver to the shoulder or side of the road out of traffic lanes as soon as possible.
- Stop safely – Allow the car to coast to a stop if possible. If not, brake gently to avoid locking up the wheels.
- Shift to Park – For automatic transmissions, shift to Park to lock gears and prevent rolling.
- Set parking brake – Make sure car won’t roll by firmly applying the parking or emergency brake.
- Hazard lights – Turn on hazard flashers to alert other drivers of your stopped vehicle.
- Call for help – Call a towing company or roadside assistance to have your vehicle brought to a repair shop.
Aside from moving to a safe location, your main priorities are to avoid traffic dangers from the disabled vehicle and get help to have it towed. Do not attempt to drive any further as doing so can completely ruin the transmission.
How to prevent transmission failure while driving
Proper maintenance and driving habits can help prevent sudden transmission failure while on the road:
- Check transmission fluid – Regularly check levels and top up low fluid to avoid leaks or low levels.
- Change transmission fluid – New fluid helps keep components lubricated and cooled.
- Address leaks immediately – Identify and repair any transmission fluid leaks right away.
- Watch transmission temperatures – Don’t overload or overwork the transmission to avoid overheating.
- Tune up your vehicle – Replace filters, spark plugs, wires, etc. per the maintenance schedule.
- Be gentle when driving – Avoid aggressive jackrabbit starts and abrupt stops.
- Listen for warning signs – Address any hesitation, slipping or unusual noises promptly.
- Consider a transmission flush – Flushing fluid can help extend the life in high-mileage vehicles.
While unexpected transmission failure can still occur, your best chance for avoiding it is thorough preventive maintenance and cautious driving habits.
Can you drive with a bad transmission?
Once your transmission has failed or is showing signs of failure, it is not recommended to continue driving the vehicle. Here are the risks of driving with transmission problems:
- Getting stranded – The transmission may completely fail, stalling the vehicle and leaving you stranded in an unsafe situation.
- Increased repair cost – Continuing to drive can turn a minor repair into a complete transmission rebuild or replacement.
- Safety hazard – Slipping gears make it difficult to accelerate or maintain speeds needed for safe driving.
- Further damage – Driving with issues like overheating or leaks can ruin seals, gears, electrical components, etc.
The repairs required for a severely damaged transmission often exceed the value of an older vehicle. Your best bet is to stop driving immediately and call for vehicle transportation to a repair shop.
How much does it cost to replace or repair a transmission?
Transmission repairs or replacements can be very expensive depending on the make, model and type of transmission. Here are some average estimated costs:
| Repair Type | Average Estimated Cost |
|---|---|
| Replace transmission fluid | $80 – $250 |
| Replace transmission filter | $180 – $450 |
| Repair minor leak | $200 – $400 |
| Replace torque converter | $500 – $1,500 |
| Replace solenoid | $500 – $1,500 |
| Remanufactured transmission | $1,500 – $3,500 |
| New transmission replacement | $4,000 – $8,000 |
Repair costs for minor issues like fluid changes and leaks will be at the lower end of the price scale. But once hard parts like solenoids, converters or complete transmissions need replacement, costs can rapidly exceed $1,000 and may not be worth it on some older vehicles.
Factors that affect transmission repair and replacement costs
Several factors can influence the costs of transmission repairs:
- Make and model – Luxury and performance brands are more expensive.
- Transmission type – Manual vs. automatic, number of gears, etc.
- Age and mileage – Extensive repairs are more likely on higher mileage vehicles.
- Damage extent – Minor issues can be fixed individually. Complete failures require full replacements.
- Shop fees – Repair shop hourly rates, parts markups and diagnostic fees vary.
- Location – Labor and part rates are higher in metropolitan areas.
Signs you need transmission repair or replacement
Watch for these key signs that indicate the need for transmission repair or replacement:
- Difficulty shifting gears
- Gears slipping under acceleration
- Burning smell or fluid leaks
- Abnormal noises during operation
- Visible damage like cracks or loose parts
- Check engine light illuminated
- Transmission overheating and losing effectiveness
- Metal flakes or debris in the transmission fluid
- Failure to engage into or switch between gears
Repairs are typically needed if you notice shifting delays, slipping, burning smells or abnormal sounds. If the transmission is totally unusable and damaged internally, a full replacement will be required.
How to diagnose transmission problems
Diagnosing transmission issues properly is key to making the right repairs. Here are some tips for diagnosis:
- Note symptoms – Pay attention to any symptoms you notice while driving.
- Check fluid – Low, dirty or smelly fluid points to larger problems.
- Inspect underneath – Look for any visible leaks, damage or loose connections.
- Scan computer – The onboard computer stores helpful diagnostic trouble codes.
- Road test – A test drive lets a mechanic experience the problems firsthand.
- Leak checks – Special dyes can pinpoint the source of fluid leaks.
- Fluid pressure test – Checks if internal hydraulic pressure is adequate.
- Microscopic analysis – Small metal shavings in the fluid indicate wear and tear.
A transmission shop will utilize these various methods to diagnose where the problems originate within your transmission system. This informs them about what specific repairs need to be made.
When do you need a new vs. rebuilt transmission?
For a badly damaged transmission, a replacement will be necessary. Here are some signs it’s time for a new or rebuilt transmission:
- Failed gears – Damaged, worn teeth prevent gears from meshing properly.
- Clutch pack failure – Burnt, warped or worn clutch plates need replacement.
- Cooler line leaks – Damaged internal cooler lines mix coolant and transmission fluid.
- Failed pump – Low pressure from a worn pump allows slipping and overheating.
- Electrical issues – Shorts in solenoids or wiring harnesses require replacement.
- Broken hard parts – Cases, shafts and other internal parts can break from wear or abuse.
- Excessive wear – High mileage transmissions wear internally and no longer function properly.
Rebuilds are only worth it on vehicles with lower miles that have developed limited internal damage. But extensive wear, broken parts or electrical issues will require complete new or remanufactured transmission units.
Can you repair a transmission without removing it?
Some minor external transmission repairs can be completed without full removal, like:
- Fluid, filter changes
- External linkage adjustments
- Electrical component access
- Leak repairs
- Throttle valve adjustments
- External sensor replacements
However, if internal hard parts like gears, bands, clutches or shafts need replacement, the transmission will have to be removed from the vehicle for disassembly. Some main reasons full removal is required include:
- Access to internal components
- Ability to disassemble case and inspect all parts
- Remove debris and flush contaminated fluid
- Repair housing leaks or damage
- Replace seals, bearings, bushings
- Adjust clearances of internal moving parts
- Modify internal components for upgrades
So while some minor repairs can be made externally, any major rebuild or overhaul will require the transmission to be taken out of the vehicle.
Conclusion
A transmission failure while driving can be frightening and dangerous. But understanding the common causes, warning signs and smart actions to take can give you confidence to deal with this situation safely until repairs can be made. While costs for rebuilt or replacement transmissions can be high depending on the damage, they are necessary expenses to get your vehicle back on the road operating smoothly.