How Hard is It to Replace Synchros in a Transmission: A Comprehensive Guide

Replacing synchros in a transmission can be a difficult task, requiring specific tools and experience. It is best left to professionals or those with advanced mechanical knowledge.

The transmission plays a crucial role in the functionality of a vehicle. It ensures that the engine power is transmitted to the wheels and allows the vehicle to move. Inside the transmission are synchros, which are small components that allow the gears to mesh smoothly and engage without grinding. Over time, synchros can wear out and need to be replaced.

While it is possible to replace synchros yourself, it can be a challenging task. It requires specialized tools and a solid understanding of automotive mechanics. Inexperience or mistakes in the replacement process can result in significant damage to the transmission or other vehicle components. Therefore, it is recommended to seek the services of a professional mechanic for this task.

What Are Synchros And Their Role In A Transmission?

Synchros, short for synchromesh, are components within a manual transmission that allow for smooth gear changes. In simpler terms, they synchronize the rotational speeds of the transmission and engine to ensure the proper gear is selected. Without the synchros, gear changes would be rough, and the transmission would be more likely to grind gears, which can lead to damage.

Signs Of Damaged Or Worn-Out Synchros

It’s important to be aware of the signs that your synchros may be damaged or worn out, as replacing them before they completely fail can save you money and prevent further damage to your transmission.

  • Difficulty shifting gears or grinding noises when shifting gears
  • A noticeable delay when changing gears or a “slipping” feeling between gears
  • The transmission will pop out of gear on its own

Why Replacing Synchros Is Important For Transmission Maintenance

The synchros play a crucial role in maintaining the health of your transmission. Without them, the transmission would be subject to increased wear and tear, which could eventually lead to total transmission failure. Replacing worn-out synchros extends the lifespan of the transmission, saves money in the long run, and ensures a smoother ride.

Understanding synchros in a transmission is vital for knowing when it’s time to replace them. Signs of damage or wear can lead to further transmission damage, and replacing the synchros in a timely manner is important for the overall health and longevity of the transmission.

Steps To Replace Synchros In A Transmission

Replacing synchros in a transmission is a challenging task; it requires patience, a good understanding of the vehicle’s mechanics, and the right tools. If you notice grinding noises or difficulty shifting gears, it might be time to replace the synchros in your transmission.

In this blog post, we will outline the steps involved in replacing the synchros in a manual transmission.

Necessary Tools And Materials

The first step in replacing synchros is to ensure that you have the necessary tools and materials required for the job.

  • Socket set
  • Torque wrench
  • Screwdrivers
  • Pry bars
  • Hammer
  • Gear puller
  • Bearing separator
  • Dial indicator
  • Replacement synchros
  • Transmission fluid
  • Gasket maker

Preparation Steps Before Disassembling The Transmission

Before disassembling the transmission, several preparatory steps need to be done to ensure successful replacement of synchros.

  • Removing the battery and disconnecting the negative cable
  • Draining the transmission fluid
  • Removing the shifter linkage
  • Removing the drive shaft and starter motor
  • Marking the alignment of the bell housing and transmission case
  • Supporting the transmission with a transmission jack

Removing The Transmission From The Vehicle

Once the preparatory steps are taken, the next step is to remove the transmission from the vehicle.

  • Removing the crossmember
  • Unbolting the transmission from the engine
  • Gradually lowering the transmission with the jack

Disassembling The Transmission To Reach The Synchros

Now it is time to disassemble the transmission to reach the synchros.

  • Removing the transmission cover
  • Removing the gears
  • Removing the synchronizer hub
  • Removing the synchro sleeves and rings

Diagnosis And Inspection Of Gears And Synchros

Before removing and replacing the damaged synchros, you need to examine the gears and synchros carefully.

  • Checking the gears for signs of wear and tear
  • Checking the synchros for signs of damage or uneven wear
  • Checking the synchro sleeves and rings for wear or damage

Removing And Replacing The Damaged Synchros

If you find any damaged synchros, they must be removed and replaced.

  • Removing the damaged synchros using a gear puller and bearing separator
  • Installing new synchros, sleeves, and rings
  • Lubricating the synchros with transmission fluid

Reassembling The Transmission

Once the damaged synchros are replaced, it is time to reassemble the transmission.

  • Reinstalling the synchronizer hub and gears
  • Replacing the transmission cover
  • Applying gasket maker to the transmission cover
  • Bolting the transmission to the engine

Reinstalling The Transmission Into The Vehicle

The final step in replacing synchros is to reinstall the transmission back into the vehicle.

  • Raising the transmission with the jack
  • Bolting the crossmember back into place
  • Reinstalling the drive shaft and starter motor
  • Refilling the transmission with fluid
  • Reconnecting the negative cable to the battery

By following these steps, you can successfully replace synchros in a transmission. It is important to take your time and work carefully to ensure success.

Synchromesh unit (Manual Car Transmission) – How it works

Common Problems That Arise During The Process And How To Troubleshoot Them

Replacing synchros in a transmission can be a complex task. Issues such as worn-out internal parts and wrong installation procedures can arise during the process, leading to more problems and extra expenses.

  • Improper synchronization – if the transmission doesn’t shift easily after replacing the synchros, it may be due to synchronization problems. You can try adjusting the shift linkage or inspecting the clutch discs and pressure plates to troubleshoot this issue.
  • Faulty bearings – worn-out bearings can cause grinding noises and harsh shifting before eventually leading to transmission failure. You may need to replace the bearings to resolve the issue.
  • Leaks – leaks are a common issue that can arise if the transmission casing or seals get damaged during the replacement process. You should inspect the casing and replace the seals to fix leaks.

Risks Involved In Replacing Synchros Without Proper Knowledge And Training

Replacing synchros requires a certain level of skill, knowledge, and the right tools. Attempting to replace the synchros without proper training, experience, or the correct equipment can result in costly damages and increased risks.

  • Personal injury – dealing with a transmission can be hazardous due to the heavy weight and sharp edges of the components. You can sustain lacerations, fractures, or other injuries if you mishandle the transmission parts.
  • Damage to the transmission – if you’re not careful, you can damage the transmission’s internal parts, seals, and gaskets. Moreover, you can break the synchronized gear teeth and cause the shift synchronizer to fail.
  • Additional expenses – if you don’t have the correct tools and experience, you may damage the transmission during the replacement process. This scenario can lead to further expenses beyond the initial synchro replacement cost.

Safety Measures To Observe When Working With A Transmission

Working with a transmission requires careful attention to safety precautions to avoid potential injuries and damages.

  • Wear protective gear – wear gloves to protect your hands and safety goggles to shield your eyes from debris and dirt.
  • Work in a well-lit and ventilated area – choose a well-lit workspace that provides adequate room and ventilation to avoid accidents and fumes exposure.
  • Use proper equipment – use proper lifting equipment to handle the heavy transmission parts safely. Also, use specific tools to disassemble and install the synchros to avoid any damage to the transmission.
  • Ask for assistance – working with a transmission can be difficult, and it’s easy to make a mistake. If you’re unsure about a particular step or action, ask for assistance from an experienced technician.

By following these safety measures, you can protect yourself and the transmission from potential harm.

Costs And Time Required

If you’re experiencing transmission issues, it could be due to a faulty synchro. A synchro ensures smooth shifting between gears, but they can wear out over time and may require replacement. But how hard is it to replace synchros, and what can you expect in terms of costs and time?

Let’s explore these questions below.

Factors That Influence The Overall Cost Of Synchro Replacement

There are several factors that can affect the cost of replacing synchros in your transmission.

  • The make and model of your vehicle
  • The severity of the damage to the synchros
  • The cost of labor in your area
  • The cost of parts and supplies
  • Whether you choose to replace other worn components, such as bearings or gears, at the same time

Average Cost Of Synchro Replacement

The cost of replacing synchros can vary widely depending on the factors mentioned above. However, as a general rule, you can expect to pay between $500 and $1,500 for the parts and labor required for this repair. Keep in mind that if other components need to be replaced, such as bearings or gears, the cost will be higher.

Time Required To Replace Synchros

Replacing synchros is a complex and time-consuming repair, so you can expect it to take several hours. The exact amount of time required will depend on the make and model of your vehicle, as well as the extent of the damage to the transmission.

However, as a general rule, you can expect the repair to take between 4 and 8 hours of labor.

Replacing synchros in a transmission is a complex and time-consuming process that can also be costly. If you’re experiencing transmission issues, it’s best to have your vehicle inspected by a qualified mechanic to determine the extent of the damage and the most cost-effective repair option.

Importance Of Professional Help

If you’re having trouble shifting gears and hear strange noises coming from under the hood, then chances are there’s an issue with your car’s transmission. One of the most common problems that car owners face is with the synchros. While it’s possible to replace them yourself, it’s important to consider seeking professional help.

In this section, we’ll discuss the benefits of seeking professional assistance, when to take your vehicle to a transmission shop, and choosing a qualified transmission specialist.

Benefits Of Seeking Professional Assistance From A Mechanic Or Technician

When it comes to transmission repairs, it’s best to leave it to the professionals. Attempting to replace synchros yourself may seem like a good idea, but it can lead to expensive mistakes.

  • Expertise and experience: professional mechanics and technicians have years of experience and expertise in repairing transmissions. They have the know-how to identify the issue and use the right tools to fix it.
  • Save time and money: while diy repairs may seem cost-effective, it can lead to further damage and can end up being more expensive in the long run. Seeking professional help, on the other hand, can save you time and money.
  • Warranty: if you get your transmission repaired by a professional, you may get a warranty on their work. This will give you peace of mind and protect you from future expenses.

When To Take Your Vehicle To A Transmission Shop

If you’re experiencing any of the following problems with your vehicle’s transmission, then it’s time to take it to a transmission shop:

  • Strange noises: if your car is making unusual noises while you shift gears, then there’s definitely an issue.
  • Difficulty shifting gears: if your car is having trouble getting into gear or the gears are slipping, then it’s a sign that your synchros may need to be replaced.
  • Leakage: if you notice any red fluid leaking from your vehicle, then it’s likely that the transmission is leaking.

Choosing A Qualified Transmission Specialist

When you take your vehicle to a transmission shop, it’s important to choose a qualified transmission specialist.

  • Experience: look for a shop that has been in business for a while and has experience in repairing transmissions.
  • Reputation: check the reviews and ratings of the transmission shop before taking your car to them.
  • Certifications: make sure that the transmission specialist you choose is certified and has the necessary qualifications.

By seeking professional help, taking your vehicle to a transmission shop when necessary, and choosing a qualified transmission specialist, you can ensure that your vehicle’s transmission is repaired effectively and efficiently.

Frequently Asked Questions On How Hard Is It To Replace Synchros In A Transmission

What Are Synchros In A Transmission?

Synchros in a transmission are small metal rings that synchronize the speed of the gear and the engine to ensure smooth shifting between gears.

What Are The Signs Of Bad Synchros?

If you are experiencing grinding noise, difficulty in shifting gears, or gear slipping, it may indicate bad synchros.

Can You Replace Synchros Yourself?

Replacing synchros in a transmission requires specialized tools and expert skills. It is not recommended to attempt it yourself without proper knowledge.

How Much Does It Cost To Replace Synchros?

The cost of replacing synchros depends on the make and model of the vehicle and the extent of damage. On average, it can cost between $1500 to $2500.


Overall, replacing synchros in a transmission is not an easy task. It requires knowledge, expertise, and specialized tools to do it correctly. However, it is definitely doable by experienced mechanics and automotive enthusiasts. If you’re up for the challenge, remember to take your time and be patient as every step should be performed carefully and correctly.

But if you don’t have the expertise or experience, it might be best to leave it to the professionals to avoid causing more damage to your vehicle. Remember, your transmission is an essential component of your car, and proper maintenance and care should always be a priority.

By following these tips and taking the necessary precautions, you can ensure that your vehicle will continue to function at its optimal level for years to come.