Why Your Car Won’t Shift Into Gear 

Being able to shift into gear is a critical part of driving any car. Whether your vehicle has an automatic transmission or a manual transmission, if you can’t shift into gear then you can’t drive anywhere. Transmissions are fairly reliable components in most cars, but like any part of your vehicle, they can experience issues over time. And one of those issues can be the inability to shift your car into gear.

There are many different reasons why a car will have trouble shifting into gear. Some of the reasons are relatively easy and affordable fixes, while others are a bit more complicated and pricy. But regardless of what’s causing your car to struggle with shifting into gear, you’ll want to fix it as quickly as possible.

Dirty Transmission Fluid

hand adding transmission fluid to their car
Degraded transmission fluid can cause damage to your transmission.

Just like engines, transmissions rely on a lubricating fluid. This fluid allows various parts of the transmission to move without creating damaging amounts of friction. In an automatic transmission, the fluid also serves as a coolant to keep the transmission from overheating.

While there are many different kinds of transmission fluids, every car with a transmission uses one. And just as with motor oil, transmission fluid can break down over time as it builds up contaminants and begins to degrade. Old, degraded transmission fluid can cause damage to your transmission, and eventually lead to a car that won’t shift into gear. If this happens you’ll want to change the transmission fluid, and also check to make sure your transmission isn’t badly damaged.

Changing transmission fluid is a relatively easy task, and one that usually costs between $100 and $200 if you take your car to a mechanic. If you choose to change the fluid yourself, you basically need to just follow the same steps as replacing your oil. Find the transmission drain plug, unscrew it, drain the fluid into a catch pan or bucket, screw the plug back in, and refill the transmission with new fluid.

Worn Out or Broken Clutch

Duralast Clutch
An inability to shift into gear could be due to a worn out or broken clutch

If your car has a manual transmission, then an inability to shift into gear could be due to a worn out or broken clutch. The average clutch should last at least 60,000 miles before wearing down, and many will last well past 100,000 miles. However, it’s not unheard of for clutches to crack unexpectedly after only 20,000 or 30,000 miles. 

Since you have to engage the clutch in order to put your car in gear, a broken or worn down clutch will result in an inability to shift your car into gear, and you’ll need a new clutch before you can start driving again. Replacing a clutch at home is a serious task. You have to disconnect the clutch from the transmission and remove it, then use a clutch alignment tool to place the new clutch in, before reconnecting it to the transmission. This repair usually costs upwards of $1,000 if you go to a mechanic, but a DIY job might only cost a few hundred dollars.

Malfunctioning Torque Converter or Clutch Master Cylinder

The torque converter and clutch master cylinder serve similar purposes, just in different cars. Automatic transmissions rely on torque converters, while stick shifts use clutch master cylinders. In short, both of these parts serve to engage and disengage the transmission from the engine. A torque converter contains a lot of different parts, and any of them can wear down and die over time. It’s less common for a clutch master cylinder to wear out, though it can happen. The clutch master cylinder is part of a hydraulic transmission system, so a more common issue is air in the system, or hydraulic fluid that needs to be replaced. 

Any of these issues can keep the torque converter or clutch master cylinder from allowing the transmission to engage and disengage, which means your transmission could get stuck and not be able to shift into gear. Replacing a torque converter or clutch master cylinder is a big task. For a torque converter, begin by removing the bolts that connect the driveshaft to the rear axle, then remove the driveshaft (you’ll need the car in neutral for that step). Then remove the filler tube and disconnect the torque converter from the transmission. To finish, remove the transmission, pull out the torque converter from the input shaft, place in the new torque converter, and put everything back in reverse order.

For a clutch master cylinder, use a vamp pump to remove the brake fluid from the reservoir, then remove the hydraulic line from the master cylinder. Remove the cotter pin, anchor pin, and mounting nuts, then take out the clutch master cylinder. Secure the new master cylinder, remove the bleeder screw, and fill the reservoir with brake fluid, then prime the cylinder and install the reservoir cap. Finally, install the master clutch cylinder back into the firewall, then reinstall the mounting nuts, anchor pin, and cotter pin. 

Damaged Transmission Linkage

Both automatic and manual transmission rely on a transmission linkage, which connects the shifter in the car’s cabin to the actual transmission. The linkage can break or become dislodged, effectively disconnecting your car’s shifter from the transmission itself. When this happens, you probably won’t be able to shift into gear. 

Fixing a broken transmission linkage depends on where the part is damaged, but it’s usually a straightforward process. 

Malfunctioning Computer

Computers play a big role in modern cars. The engine control unit takes information and uses it to determine when a car with an automatic transmission should shift. If the engine control unit is malfunctioning, the transmission may never get the signal to shift gears. 

Replacing an engine control unit is straightforward. Simply disconnect the battery, disconnect the engine control unit, remove it, replace it with a new one, connect the new engine control unit, and reconnect the battery. 

You can find the parts and tools that you need for all these transmission repairs at AutoZone, where Free Next-Day Delivery is available on eligible orders. AutoZone also offers the convenience of Same-Day In-Store or Curbside Pickup, so you can get back to repairing your car as quickly as possible. 

Advice, how-to guides, and car care information featured on and AutoZone Advice & How-To’s are presented as helpful resources for general maintenance and automotive repairs from a general perspective only and should be used at your own risk. Information is accurate and true to the best of AutoZone’s knowledge, however, there may be omissions, errors or mistakes.

Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

FREE Loan-A-Tool® program requires returnable deposit. Please note that the tool that you receive after placing an online order may be in a used but operable condition due to the nature of the Loan-A-Tool® program.

Related Posts