Home Transmission & Drivetrain Car Won’t Go Into Gear – Why Can’t Your Transmission Shift?

Car Won’t Go Into Gear – Why Can’t Your Transmission Shift?

by Kelvin Yates

Your car is a maze of components working in unison with one another. As they say, the more parts a certain machination has, the more likely it is to fail or malfunction. With that being said, it can be a bit ironic when these breakdowns do happen, not that they should be taken lightly. The transmission has the sole purpose of changing gears. But what happens then, when your car won’t go into gear?

Sure, at least it’s better than say, the brakes failing and not being able to stop you careening into a tree. Nevertheless, a gearbox that won’t shift is still quite dangerous. Imagine if you’re on the move on the highway, and suddenly find that you can’t get up to the oft-high speeds with other traffic. Or, you find yourself at a set of lights, and now are incapable of moving or getting out of the way.

Besides being a pain in the backside, having your car won’t go into gear could put you in a bind. One where you’ll be constrained in the speed you’re able to travel. Plus, lacking any control in what direction the car will head towards, or completely immobilizing you. Additionally, the fact that it’s related to your gearbox could entail a pricey repair. But when your car won’t go into gear, is it a complex fix?

What Should You Do When Your Car Won’t Go Into Gear?

First and foremost, what should you do when you’re instantly thrust into a situation where your car won’t go into gear? Well, if you’re still moving by the time you’re reading this, then gently slow down and pull over to the side of the road that’s safe from oncoming traffic. Should you be static and have yet to move at all, leave your car be. Or, push it to the side of the road if it’s blocking traffic.

The most important thing to note is that you should stop your car at once! And, don’t use it until this transmission gremlin can be solved. Choosing to continually drive your car with a faulty transmission, even if you’re proceeding at a slow and steady pace, is a terrible idea. What issue you have can likely be repaired without difficulty. However, putting more strain on it could damage it further.

Car Won't Go Into Gear

At this point, keep your car turned off, and let’s see what we can learn about how your car won’t go into gear. In many cases, you can diagnose and sometimes even troubleshoot this issue on the fly in a pinch. Although, there will be occasions when the cause of the issue lies much deeper and requires a more thorough examination. Either way, it’s wise to have your car towed to the nearest workshop.

Here, the mechanic will start poking around to see what’s behind your car won’t go into gear. Based on what type of transmission you have, the underlying problems and solutions will differ. With that in mind, we’ll look at the reasons, as well as respective solutions for cases where your car won’t go into gear. Our guide will cover both automatic and manual gearboxes, starting with the former…

Automatic Transmissions, And Why Your Car Won’t Go Into Gear

Automatic gearboxes have been around since the 1940s. In its heyday, these autos were actuated by more mechanical means. Its old-school operation relied on the hydraulic pressure of the transmission fluids and vacuum physics to assess the engine’s load and your car’s speed. In the past few decades, however, the inner workings of automatics have transitioned to using more efficient electrics.

Modern autos feature a TCM (or Transmission Control Module), which works as the central analysis and computing brain of your automatic gearbox. It’s then connected to various sensors around the transmission, as well as your car’s primary computer, the ECU (or Engine Control Unit). This way, the gearbox can determine your vehicle’s engine speed, rolling velocity, RPMs, or throttle position.

Electronic signals are then sent to the shift solenoid and valve body, respectively. Together, they both control the crucial flow of pressurizing hydraulic transmission fluids, which thus engages the correct gearing when you need it. As you can imagine with this summary of how autos work, the issues that you may come across may not only be mechanical in nature. The electrics might go wrong, too.

Here are some of the most common causes why the automatic transmission is the reason why your car won’t go into gear…

1. Malfunctioning Or Glitchy ECU And/Or TCM

As we mentioned earlier, autos of the past few decades are reliant on electronic signals to determine the gear shifts. Should these fail, it can prompt symptoms to appear like cars won’t go into gear. Any breakdowns, in this case, may also compromise the usability of the gearbox, and cause other issues to appear. For example, your car not changing gears smoothly, or if it bumps you into the wrong gears.

The fault can be pinned down to your car’s ECU or TCM. Although, it might also be possible that the rest of the electronics might have some faults in them, too. Say, a defective throttle position sensor, or a broken vehicle speed sensor. If both of the latter were to break, for instance, it can’t provide the right information to your car’s ECU and TCM. Subsequently, the transmission can’t shift well accordingly.

Car Won't Go Into Gear

Still, this issue might otherwise be caused by physical damage to the ECU and TCM modules. On top of that, the programming and software in the ECU or TCM might’ve been compromised. This usually happens with new cars that have just been unveiled to the market for the first time. Or, if you’d get a major software update with your car’s computers that don’t play well with the transmission.

Your only route for fixing this problem would most likely require a visit to your local dealership, or a transmission specialist. Most regular workshops should be more than competent enough, provided they have the spare parts in store. If the underlying cause of the electronics glitches that cause your car to not go into gear happen to be malfunctioning sensors, they need to be replaced.

1.1. Car Won’t Go Into Gear, Solution No. 1: Re-Flash Or Replacement

  • Throttle Position Sensor – Among the cheaper fixes on this list, the sensor itself would cost around the $60 to $200 mark. On average, most vehicles’ throttle position sensors will only set you back $100 or so, but it may cost you more for higher-end vehicles. Labor charges are likely to be relatively small as well, usually under $100. Altogether, you’re looking at $150 to $400 for a full replacement.
  • Vehicle Speed Sensor – Sometimes referred to as the ‘transmission speed sensor’, replacing it will cost you somewhat similar to a throttle position sensor. The sensor may cost you as little as $20 at times, but you should expect a figure of around $50 to $150 for most vehicles. Labor fees will typically cost less than $100, too. In all, a replacement job will bill you around $130 to $300 for most vehicles.

  • TCM Re-Flash (Reset) – A simple bug in the TCM’s software could be the cause of why your car won’t go into gear. In that case, you could get it going again with a quick update, or perform a hard-reset of the module entirely. If your vehicle is a part of the recall or under warranty, the local dealer may perform this for free. Otherwise, it’ll cost you around $75 to $250 for a software reset.
  • TCM Replacement – Unfortunately, swapping out the TCM unit will always be expensive. You may be lucky and get refurbished TCMs for under $150. For the most part, a complete TCM kit could cost you $450 or up to $1,000. In addition, the intensive labor required could add another $50 or up to $400 depending on your car. In short, a TCM replacement may cost you $500, or upwards of $1,400.

2. Dirty, Old, Worn-Out, Or Low Amount Of Transmission Fluid

This issue applies to both automatics, as well as manuals. The hydraulic transmission fluids perform numerous roles within the gearbox. As for their similarities, the “gearbox oil” provide lubrication and cooling to the transmission. Its functionality, therefore, is akin to what motor oil does for your car’s engine. However, transmission fluid is consequential to the operation of automatic gearboxes.

In other words, autos won’t work without it, which may be why your car won’t go into gear. Gearbox oil – or more accurately, we’ll define it as ‘transmission fluid’ – is a core part of your torque converter. This is the automatic equivalent of a manual clutch, whereby it disconnects the transmission from the engine during gearshifts. Torque converters rely solely on pressurized fluid dynamics to function.

With that being said, transmission fluids are not designed to last for an eternity. Over time, it’ll start to accumulate countless tiny particles and contaminants in the transmission, such as dirt and debris. Alternatively, all that prolonged exposure to heat can burn the fluid out, resulting in it not chemically adhering or performing well as it used to. Last but not least, a fluid leak might be involved.

2.1. Car Won’t Go Into Gear, Solution No. 2: Fluid Change Or Sealing

If this is the case for you, then fixing it will be just as simple as flushing the old transmission fluid out. Then, promptly replace it with a fresh batch. You’re recommended to do this as a part of your regular service interval anyways. For most vehicles, you ought to flush and replace the fluid every 2 years, or around 30,000 miles. That said, some technicians are happy to claim an interval of 100,000 miles.

So, you should refer to your car’s owner’s manual to see when a recommended fluid change is best for your particular car. On average, you can expect an invoice of approximately $150 to $250 for a flush and change job. Although, some might charge upwards of $400 for the same job. But what if the mechanic cracked open your gearbox to find it bone dry? If so, then you have a leak to deal with.

Transmission fluid leaks can appear in several places, with varying complexities and costs attached to patching them up. Here are some of the most common places where fluid leaks may appear, and the price that you’ll have to pay for a repair:

  • Fluid Pan Gasket – $150 to $200 (or as little as $20 if all you need is a simple sealant)
  • Fluid Pan Drain Plug Gasket – $250
  • Transmission Cooler Lines – $100 to $500 (there are repair or rebuild kits for $200 or less)
  • Input/Output Shaft Seals – $200 to $400 (similarly, it may cost as little as $20 with a sealant)
  • Valve Body – $200 to $500
  • Shift Solenoid – $100 to $300
  • Torque Converter – $600 to $1,100
  • Entire Transmission – $2,000 to $8,000 (as a worst-case scenario, if the leakage is too heavy)

3. Shift Lock Preventing You From Changing Gears

In many of today’s crops of automatic-equipped cars, you may stumble upon something called a shift lock. This is a system that locks the transmission in place, preventing you from accidentally changing gears when you didn’t mean to. Usually, the shift lock will only unlock itself when you click the button found on the gear lever, and press the brake pedal at the same time. Then, you may shift as usual.

This is to ensure that you won’t unintentionally shift out of Park or Reverse. Both scenarios are quite deadly, as rolling cars have resulted in deaths and tragic accidents before. A key safety feature then, but it also functions as a safety net to prevent accidental gear changes. Changing into Reverse while driving, for example, can guarantee a quick death for your transmission. Or at least, excessive wear.

Car Won't Go Into Gear

3.1. Car Won’t Go Into Gear, Solution No. 3: New Battery Or Shift Lock

Unfortunately, there may be times when the shift lock is faulty. Generally, we attribute the cause to the shift interlock solenoid. Additionally, some cars have electronic shift locks. Therefore, if your car’s battery was flat, you can’t shift at all. Your two solutions to try and get it working would be to jump-start the battery or replace it outright. A new 12V battery will usually cost around $100 to $250.

Otherwise, the shift interlock solenoid may have worn out. A total replacement cost for this unit will tally to around $180 to $220. The good news here is that most cars (but not all) have some override for the shift lock. It usually involves sticking your ignition key into a slot in the center console. This is a great way to get your car going in a pinch, but we’d still recommend getting it fixed afterward.

Manual Transmissions, And Why Your Car Won’t Go Into Gear

I’m sure you already know how a manual works by now. Every action of changing gears is manually-actuated, rather than letting the transmission shift the gearing automatically for you. Its operation involves you pressing the clutch pedal. This forces the clutch to disengage the transmission from the engine. In automatics, the same task is handled by the torque converter, as we detailed earlier.

Next up, you’ll have to physically move the gear lever into the gear ratio you want, while still keeping your foot on the clutch pedal. Then, and once you’ve picked a gear, you may depress the clutch pedal to continue driving in that selected gear. This process goes for every gear change, which includes the forward driving gears, as well as Neutral and Reverse. Of course, you won’t find Park on a manual.

It’s for this reason why most enthusiasts choose manuals over autos, owing to its engagement. Yet, a vast majority would much prefer the convenience of an automatic instead. Since the operation of the manual gearbox is dependant on mechanical linkages, these are where the faults lie. You won’t find electronic gremlins as the primary cause, as manual gearboxes are mostly mechanical in nature.

Here are some of the most popular reasons why your manual gearbox is causing your car to won’t go into gear…

4. Worn-Out Or Burnt-Out Clutch

As manual cars have a direct connection between the actual clutch and the clutch pedal, it’s easy to spot any issues with it. Symptoms of a worn-out or broken clutch can be felt right away if the pedal feels a bit too stiff. During gear changes, you may also hear unpleasant grinding or crunching sounds emanating from the gearbox. Or, you might smell a faint but heaty scent of a burned-out clutch.

Regardless, the clutch is one of the most important parts of any manual-geared car. It’s worth saying that the clutch is a system that consists of several constituent parts. These include the primary clutch disc, as well as the throw-out bearings and pressure plates. Additionally, you can count the flywheel in, too. The flywheel is what harmonizes the connection between the gearbox and the engine.

Burnt Out Clutch Replacement Repair Transmission

Despite how crucial it is to your car’s operation, the clutch is privy to wearing or burning out and fails within the lifespan of your car. How long a clutch would last depends quite heavily on what vehicle it powers, and how careful are you about using it. Some clutches wear out after just 30,000 miles. Yet, most typically last over 150,000 miles before a serious reconditioning or replacement is necessary.

4.1. Car Won’t Go Into Gear, Solution No. 4: Clutch Replacement

As it’s a commonly replaceable item, a technician should easily be able to spot if the clutch needs a hearty replacement. On average, most vehicles will average about $450 to $650 for a replacement clutch, including the cost of labor. Nevertheless, that repair bill may rise to $750 or higher if your car is complicated to work with, and requires a specialty, performance, or heavy-duty clutch.

And since the clutch consists of numerous parts on its own, the cost of replacing each one differs:

  • Clutch Kit – $300 (this includes the clutch disc, throw-out bearings, and pressure plate)
  • Flywheel – $500 (this is for a total replacement, not a resurfacing job, which can cost as little as $50)
  • Hydraulic Pumps – $100 to $300 (these pumps are specific to hydraulic clutches)

5. Faulty Or Worn-Out Gear Synchronizers

In older cars, trying to change gears smoothly will always be challenging, as it requires you to tip-toe with the engine revs. Since the engine speed can revolve thousands of rotations per minute (RPM), it requires precise actuation to the transmission to avoid jerking or grinding. So, you’re left with having to time and match your gear changes carefully with the RPMs. Thankfully, modern cars are better.

They have a component called a gear mesh synchronizer – or commonly referred to as “synchros” – as a feature to make gear changes smoother and easier. As its name implies, it synchronizes the gearing with your rapid engine speeds and shifts into gear accordingly. These synchros can, unfortunately, wear out as they age. Normally, their aging is premature, due to rough or aggressive shifting.

5.1. Car Won’t Go Into Gear, Solution No. 5: Synchro Replacement

A synchro replacement is going to be exceedingly costly, as it requires taking apart the transmission to get access to it. Parts are relatively affordable, setting you back roughly $200 to $400 for a set of synchros. This isn’t so bad if not for the labor rates. It can take days to slowly crack open and take apart the gearbox. That’s before swapping in the new synchros and putting it all back together.

On average, you can expect the intensive labor to cost you between $600 to $1,400. This should all depend heavily on how easy the synchros are to get at in your particular vehicle. On top of that, we should also mention that your car has more than one synchronizer. Usually, it’s one synchro for each gear ratio. So, a 5-speed manual gearbox will have 5 separate synchros, at differing costs.

The $200 to $400 figure will apply to the 1st gear synchro. The price is generally even across the 2nd, 3rd, 4th, 5th, and so on. Therefore, don’t be surprised if the bill to replace the synchros rounds up to $2,000 or more. Albeit, you can replace just one or a few synchros, if the others are fine. That said, it’s no doubt cheaper to replace faulty synchros than rebuilding or replacing the entire transmission.

6. Broken Transmission Shift Linkage

Last but not least, seeing that your car won’t go into gear could easily be caused by a fault with the actual shift linkage or gear shifter. This issue applies to manuals, as well as most automatics on the market today. With manual-operated cars, you might notice this by your clutch pedal sinking its way to the floor. Regardless, we could easily point our fingers at the transmission shift cable.

Manuals commonly have two shift cables, compared to just one for an automatic. Over time, these cables can fail owing to excessive wear or stretching. This is a more prevalent issue in manuals rather than autos. Hence, why they tend to last around 125,000 to 175,000 miles. Besides that, it’s plausible to find the shift cable being dislodged during an accident or driving over particularly harsh terrain.

Surprisingly, this seemingly simple cable can be quite costly to mend. Parts can be found for around $120 or thereabouts. Nonetheless, labor charges usually outweigh the cable itself, as accessing it can be rather tricky. In all, expect a shift cable replacement to cost approximately $250 to $350 for automatics. Since manual shift cables are more complex, the cost rises to between $200 and $450.

Transmission Repair: Top Signs to Look Out For

  • The transmission won’t engage or stay in gear may be due to low transmission fluid, shifter cable, or problems in the valve body of your automatic transmission.
  • Delayed or missing gears may be due to low transmission fluid, lack of maintenance, or engine-related issues that prevent the computer from allowing the transmission to shift into higher gears.
  • Transmission slipping or engine revving high can be caused by low transmission fluid, contamination, or internal wear and tear on transmission parts.
  • A red fluid under the vehicle is a sign of a transmission fluid leak, which can cause damage to the transmission and is dangerous if the fluid leaks on hot surfaces.
  • A burning smell is typically caused by a fluid leak or low fluid causing a burning clutch smell.
  • Buzzing, clunking, and humming noise from inside the transmission indicates a bad bearing, planetary gears damage, or other internal problem.
  • No or little power in the vehicle could be due to internal transmission problems or brakes that are dragging, among other issues.
  • Check Engine Light or Over Drive Light can indicate various transmission problems, and retrieving trouble codes will help identify the issue.
  • Gears grinding when shifting in manual transmissions is usually related to the clutch not releasing, the shift synchronizer rings worn or broken, or a shifter wear or adjustment problem.
  • Clutch pedal grabbing very low or very high can be due to problems with the linkage or hydraulic system that operates the clutch, or a worn clutch disc and pressure plate.

Final Thoughts On Why Your Car Won’t Go Into Gear

Well then, that rounds up our look at the common causes of why your car won’t go into gear, as well as its respective repairs and costs. Overall, failure to get into gear can be the result of varying issues. These can be as simple as software glitches with your ECU or TCM, which could (finger’s crossed) be fixed with a hard reset. Worst, it might necessitate a mechanic cracking your transmission open.

The complexity and price tags for solving this issue are naturally broad. From as little as tens of dollars, it can quickly skyrocket to several thousand if key internal components require replacements. Yet, it validates our point that getting this issue diagnosed as quickly as possible is far better than choosing to ignore it. Leaving it for another day will only make the problem worse, and more expensive to fix.

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