The Difference between Synchronized and Unsynchronized Gearing in Manual Transmissions

By Mister Transmission

There’s a good reason why large commercial vehicles, motorcycles, and race cars still employ an unsynchronized gearbox

For stick-shift adherents, there is no greater joy than driving a car with a manual transmission. But what’s behind the mechanics of changing gears? And from a driver’s perspective, how does manual transmission synchronized gearing compare to manual transmission unsynchronized gearing?

Most modern urban vehicles fitted with manual transmissions likely feature a synchronized gearbox also referred to as a synchro-mesh gearbox. This device keeps the gears in mesh and rotating, or they can be locked to the shaft. In other words, when you change gears, you’re locking different gears to the transmission’s input or output shaft, thereby allowing you to increase your vehicle’s speed or slow it down. The manual transmission’s synchronized gearbox is what helps you smoothly lock gears into place.

It was a remarkable evolution in manual transmissions because the synchronizer did away with the need for motorists to perform double-clutching – releasing and re-engaging the clutch twice whenever changing gears – a requirement to operate a vehicle with a manual transmission unsynchronized gearbox.

Why the Manual Transmission Unsynchronized Gearbox Still Matters

A manual transmission unsynchronized gearbox is an older design (possibly the earliest design of a manual transmission) that required a lot of effort and skill on the driver’s part. It included a sliding-mesh gearbox, and the driver would need to carefully time when to shift gears to ensure the gears were rotating at the same speed, which was no easy feat. Do it improperly, and you’ll hear grinding and other noises.

However, the unsynchronized gearbox continues to exist. You will often find them installed in transmissions for large commercial vehicles such as heavy trucks and farming machinery, as well as in motorcycles and high-calibre race cars. Why? For two reasons: synchronized manual transmissions are more prone to breakdowns, and shifting gears on a synchro-mesh gearbox is slower than the unsynchronized version.

Are you experiencing a problem with your vehicle’s manual or automatic transmission or have questions about transmissions? Visit the Mister Transmission location nearest you and get the expert help and information you need.

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Kyle Andree
I recently went in to see dez for a transmission in a 90's silverado. After he rebuilt the transmission he called me toTell me i needed a new shifter cable.i told him I didn't care about the new cable but he threw the cable in for free. Definitely good service and the price was very good too
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I went in to set up an appointment for them to see what exactly was wrong with my car, because they were busy and couldn’t see to my car they wanted to know what they were dealing with.When they saw my car Bob the chap I was dealing with advised me against driving it any further until repairs were done.I could have had a terrible accident and my car could have been totalled.If I need anything done to my car and they can do it , I’m going to them.
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I went in to set...
Blue
I went in to set up an appointment for them to see what exactly was wrong with my car, because they were busy and couldn’t see to my car they wanted to know what they were dealing with.When they saw my car Bob the chap I was dealing with advised me against driving it any further until repairs were done.I could have had a terrible accident and my car could have been totalled.If I need anything done to my car and they can do it , I’m going to them.
Date: May 14, 2022
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I went in to set...
Blue
I went in to set up an appointment for them to see what exactly was wrong with my car, because they were busy and couldn’t see to my car they wanted to know what they were dealing with.When they saw my car Bob the chap I was dealing with advised me against driving it any further until repairs were done.I could have had a terrible accident and my car could have been totalled.If I need anything done to my car and they can do it , I’m going to them.
Date: May 14, 2022
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Marty Roberts
The staff and franchise owner are trustworthy and professional. Service is excellent, being in the automotive business I have used Mister Transmission in Peterborough more than once with positive results.
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Always A1 service
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Peter Prudencio
I've had a great experience with this local auto shop: Giorgio is a fantastic business owner, with an honest and reliable work ethic, favouring and fostering long-term relationships with his customers, and offering very fair prices compared to larger dealerships and other shops. Comes strongly recommended by my neighbours, and I would vouch for his excellent quality of service as another witness to his workmanship.
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Gus is very professional, honest and his customer service is amazing. He explained everything to me so I knew exactly what he had done. I would recommend him to anyone
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Marcus W.
The gentleman at Mister Transmission was incredibly helpful and professional. He looked at my car and diagnosed that the problem wasn't the transmission itself, but likely the transmission computer.  He then helped me contact the dealer to confirm that the model had been having problems.  Rather than charging me for the repairs, he worked with me to get me the best deal.  He put the customer ahead of the bottom line, and I couldn't be more grateful for his work ethic.
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These guys are very helpful, I did not have any work done here but he still helped me on phone and answer my questions about transmission in the car I was going to buy.
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