It's never a good sign when your car starts experiencing transmission problems, so in this article, we will discuss what to do if you cannot shift into reverse. Modern transmissions are highly complex components of your vehicle, especially automatics, so there are many different parts involved, and unfortunately, many of them can fail. Using some of the best resources available, we have compiled all of the most likely reasons your transmission will not shift into reverse so you don't have to go rooting around all corners of the internet to find the solution.
Here are the common reasons a transmission will fail to shift into reverse:
- Dirty Transmission Fluid
- Low Transmission Fluid
- Bad Transmission Position Sensor (automatic transmission)
- Faulty Valve Body (automatic transmission)
- Broken Revers Gear Teeth (manual transmission)
- Broken Shifter Mechanism (manual transmission)
- Failed Lockout Ring (manual transmission)
As you can see, there are many possible reasons for your lack of reverse. Next, we will provide an in-depth explanation of each of these problems so you can better tell which one is likely the problem with your transmission.
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Why a Car Won't Go Into Reverse
Your car transmission system controls the direction in which the vehicle moves. By switching the direction of the transmission, the power from the engine makes the wheels turn in reverse.
Most vehicles in the US have automatic transmissions but some still use a manual transmission. The reasons for your car not going into reverse differ according to the type of transmission, although there are a couple of things that can happen in either a manual or automatic car.
General Reasons - Automatic or Manual
Here, we will cover the major reasons your car's transmission won't go into reverse. These are causes for this issue, regardless of the type of transmission you own.
Dirty Transmission Fluid
Over time, your transmission fluid - the oil responsible for keeping all of the transmission component operating smoothly - becomes contaminated. Thes small particles swirling around in the fluid can cause the transmission to fail, which could result in being unable to shift into reverse.
Keep in mind, however, that modern transmissions are designed to operate for many thousands of miles without needing to change it, but if your newer vehicle has over 150,000 miles, or your older vehicle (manufactured prior to 1996) has over 100,000 miles, it might be time to change out your fluid.
Low Transmission Fluid
A more common fluid-related cause of this issue is low transmission fluid. If your transmission fluid has leaked to a point where the fluid is no longer able to keep temperatures down inside the transmission, this excessive heat could effectively lock out your reverse gear. It is unlikely that this will be the only problem you experience, however, so look out for related issues such as slipping shifts.
If you think this could be your problem, simply top off your transmission fluid and see if this fixes the reverse-gear lockout. Measure your levels first, however, to check if your levels really are low.
Reasons Specific to Automatic Transmissions
Bad Transmission Position Sensor
The transmission position sensor has an important job - it tells the transmission what the shifter is trying to do. So, if this sensor is not working, it may not relay the message "Shift to reverse" to the transmission control module.
Modern vehicles will often display a check engine light when the position sensor bites the dust. Other warning signs include not being able to shift above a certain gear, not being able to start the car, and shifting into the wrong gear. Repairs for this condition include repair and replacement, so have a qualified mechanic inspect yours to find out the best course of action.
Faulty Valve Body
An automatic transmission valve body is a crazy-looking maze of channels that direct the flow of fluid (transmission or hydraulic) to the valves within your transmission. This allows the fluid to activate clutches that allow your transmission to shift.
Clearly, then, if something were to go wrong with this important piece, your shifts will suffer. Sometimes, the reverse valve malfunctions. If it becomes stuck so that the fluid cannot open it, this will cause your reverse to get locked out.
You may also experience other issues with your transmission if the valve body is faulty. There may be shifting delays, or it feels like the transmission is slipping when it shifts. If the valve body is the cause of your reverse gear issues, you will probably need to replace the entire unit, which costs between $320 and $900 on average.
Reasons Specific to Manual Transmissions
Broken Reverse Gear Teeth
This issue is most commonly found with manual transmissions because failure to shift correctly can strip the teeth off of the gears. Keep in mind, however, that it can rarely be experienced with automatic transmissions as well.
For a detailed explanation of this problem, check out this great article from the LA Times. Basically, your transmission uses two reverse gears with teeth that must interlock perfectly for the transmission to shift. If the teeth on those gears become worn down, however, they will have trouble interlocking. This usually results in a terrible grinding or clunking sound when you try to move the shifter into reverse.
Broken Shifter Mechanism
Sometimes the fault of your transmission's woes lies with the shifter itself. If this is the case with your transmission, you will likely find that you can feel this problem. The shifter will feel as though it is blocked from entering the reverse position, or it will take an excessive amount of effort to put it there.
To diagnose this problem, you will need to inspect the various components of the shifter, looking for any bent or broken cables and bushings.
Failed Lockout Ring
Modern manual transmissions come with a lockout feature that prevents drivers from shifting into reverse while the car is moving forward. However, if the lockout ring - the part responsible for blocking shifts into reverse - fails, it can prevent shifting into reverse while stationary.
If this is the case with your vehicle, sometimes you can play with the shifter for a while, moving it left and right before trying to shift into reverse again. If that doesn't work, you can try shutting your engine down, then shifting into reverse while the key is turned to the accessory or lock position. Ultimately, however, you will need to fix or replace your lockout ring.
Can a Clogged Transmission Filter Cause No Reverse?
Your transmission filter is responsible for keeping your transmission fluid clean. Like any other filter in your car, it can become clogged with contaminants. One of the warning signs that this has happened is trouble shifting into reverse. You might also hear a whine when the car is stationary and in reverse and when driving in other gears. This usually will not completely block off your reverse, but it can happen in extreme cases.
What Are Signs of a Dirty Transmission Filter?
As mentioned above, trouble shifting into reverse can be caused by a clogged transmission filter. There are other signs to watch out for, however:
Leaks
If your filter is clogged, that means it is not letting the fluid through fast enough. When the fluid gets backed up, it looks for other ways of escaping, including through the vent tube and onto the ground. So, if you see transmission fluid on the ground (usually red or pink), it might be time for a new filter.
Burning Smell
If the filter is not letting enough oil through to the transmission, some components inside the gearbox can heat up. This excessive heat buildup can result in a burning smell emanating from the car. It is important to not drive the car if you experience a burning smell like this. Stop immediately - this will allow your transmission to cool down and prevent permanent damage. Of course, the burning could be coming from somewhere else that is even more dangerous as well.
Rattle
A dirty filter can even cause your car to rattle. If you check all of the usual suspects - exhaust, bolts, and catalytic converter - and find nothing, it could be coming from your transmission. Have the filter inspected as part of your diagnostics procedure.
How Do You Know If Your Transmission Is Going Out?
Worried that your transmission is on its last legs? Aside from failing to shift into reverse (or any other gear), here are some of the main signs that mean your gearbox might soon be kaput:
- Check Engine Light
- Grinding Gears
- Slipping Gears
- Burning Smell
How Do I Know if My CVT Transmission is Going Bad?
CVTs, or continuously variable transmissions, are unlike regular automatics. They do not shift into separate gears, each with its own set ratio, like most drivers are used to. Instead, they constantly change the gear ratio in order to optimize performance and, primarily, fuel economy.
That makes it harder to diagnose a problem for some drivers because they feel different than a normal transmission. So here are the signs that your CVT is having problems:
Hesitating to Shift into Drive or Reverse
If your transmission seems to resist when you attempt to shift into either drive or reverse, this is a classic sign that something has gone wrong.
Burning Smell
As with any transmission, a burning smell can indicate that excessive heat is building up inside the gearbox. This could be caused by low transmission fluid or a clogged filter.
Leaks
Any time you notice pink transmission fluid on the ground after you have been parked, you should have your transmission checked. A CVT has many seals on the outside that can fail any cause of this leakage.
Vibrations
If your car seems to shake as you drive along, the cause could be a bad CVT. Of course, there are many other potential causes for this as well.
How Do I Know If My Shift Solenoid Is Bad?
A shift solenoid helps your car shift by regulating the fluid that enters the valve body. When your shift position sensor tells the control unit to shift, a signal is sent to the solenoid to open up and allow the fluid into the valve body. If this part goes bad, you might notice the following symptoms:
- Check Engine or Transmission Warning Light
- Transmission is Stuck in Neutral
- Delayed Shifting
- Inability to Downshift
- Rough Shifts
Can I Drive with a Bad Shift Solenoid?
Okay, so you've been diagnosed with a bad solenoid. What now - can you drive it or do you need immediate repair? Well, according to It Still Runs, you can still drive for a short period of time with a malfunctioning shift solenoid.
Your transmission will not function normally, so you might be restricted to certain gears, but the car should be able to drive, as long as you don't put too much stress on the engine. A repair should be made before too long in order to prevent causing any extra damage.
How Much Does It Cost to Replace a Shift Solenoid?
Depending on your vehicle, the cost to replace a shift solenoid usually falls between $150 and $400.
Will Your Car Start If the Transmission Is Out?
The answer is, it highly depends. It depends on what the issue is affecting your transmission, and what kind of car you own. So, it is possible that some cars will start with a bad transmission, while others will not.
For example, if you are experiencing a bad neutral switch, this will likely cause your car to not start. This part's job is to prevent the car from starting while in gear, which would make it drive off unexpectedly. If something goes haywire with the neutral switch, it can prevent your car from starting at all.
Can an Oil Change Affect the Transmission?
Changing your engine oil should not change how your transmission functions. However, if as part of your service you had your transmission fluid changed as well, you might see some differences. Hopefully, clean transmission oil will make your shifts smoother and crisper. Of course, if something was done incorrectly, such as forgetting to fill the transmission fluid back up after flushing it, this can result in catastrophic failure.
Are Transmission Flushes Bad?
Flushing your transmission - draining all of the fluid out and replacing it - sounds like a good thing to do periodically. And it usually is, as the new fluid functions better than the old, dirty fluid. Unfortunately, sometimes they can have negative consequences.
The main problem that can occur is when the new fluid flows backward through the transmission as it is added. This can break up contaminants and debris and move them around, causing problems with your transmission.
Why Is My Transmission Fluid Black?
As we have discussed, your transmission fluid should be a pink or red color. If you notice yours has turned black, this can mean it's time for service. That's because black or dark brown fluid indicates a buildup of contaminants, or that your fluid is burnt.
How Much Does Replacing a Transmission Cost?
As you can imagine, replacing a transmission is a big job, and that means it can be costly. But just how much are we talking about?
Well, according to the Transmission Repair Cost Guide, replacing your transmission can cost between $1,800 and $3,400. Going with a salvaged transmission instead of a brand-new unit will help keep those costs on the low end, but no matter what there will be between 4 and 10 hours of service factored into the cost.
Keep Shifting Smoothly!
Well, hopefully, you now have a good idea of what is causing your transmission issues and what you can do about it. It is always a good idea to have a qualified mechanic take a look if you think something is awry - after all, a small problem now costs much less to fix than a big problem later!