What Is the Difference between Constant and Sliding Mesh in a Manual Transmission?

By Mister Transmission

Driving a stick? Get to know more about the gearbox that powers your car or truck

The history of manual transmissions and their evolution is fascinating. For instance, at one time, your car’s manual transmission included either a sliding-mesh gearbox or a constant-mesh gearbox.

A manual transmission sliding mesh is typically found in older vehicles. It is, in fact, one of oldest types of gearbox. To shift between different speeds using a sliding-mesh gearbox, the gears on the main shaft are shifted right or left for meshing them with the appropriate gears on the counter shaft (this is where the phrase ‘shifting gears’ comes from).

The problem with a sliding-mesh gearbox is when changing gears, the speeds of the input and output shafts must be matched first. Otherwise, the sliding dog teeth of the meshing gearwheels do not align, and they “crash” into one another. That is why this type of gearbox is alternatively referred to as a ‘crash box’.

A manual transmission constant mesh, meanwhile, is commonplace in newer manual transmissions – notably those in large trucks and farm vehicles. All of the gears mesh together simultaneously and at all times. In other words, the gears rotate freely on the main shaft, and the gear ratios are selected by clutches that connect them to shafts to power your vehicle.

Why a Constant-Mesh Gearbox Is Your Better Option

A sliding-mesh gearbox may be mechanically efficient, but the noise it generates when changing gears, and the difficulty that was involved when changing gears left much to be desired.

In comparison, the advantages of a constant-mesh gearbox include:

  • The gears used in a manual transmission constant mesh are helical and double helical and are quieter during operation
  • Because the gears in a constant-mesh gearbox are in constantly meshing, it’s less likely to damage the gear teeth, and there’s typically less wear on the gears
  • If a driver makes a “bad” change in gears, any damage that may occur will be limited to the dog clutch

The Synchro-Mesh Gearbox Comes to the Fore

For stick-shift enthusiasts, though a manual transmission constant mesh was an improvement over the sliding-mesh gearbox, drivers still required tremendous skill to operate them. That gave way to the synchro-mesh gearbox, a unit that has many similarities to its constant-mesh predecessor since the gears are always engaged. The exception is the inclusion of a cone clutch that sits between the dog clutch and gears. That means motorists no longer have to trouble themselves with the necessity of double declutching as they would using a constant-mesh gearbox.

 

Are you experiencing transmission troubles or have questions about your vehicle’s transmission? Visit the Mister Transmission location nearest you and get the expert help you need.

image-reviews image-reviews
Customer Reviews
Good and friendly and reliable...
Albert Wilton
Good and friendly and reliable people and they work hard to get your vehicle doneService: Transmission
Date: July 25, 2021
Website: Google
Thank you, Mister Transmission! After...
Christy McMurray
Thank you, Mister Transmission! After taking my vehicle to the dealership where I bought it, and paying $150 for them to tell me what I already told them was wrong, the Dealer gave me a quote of $6,500 to replace my 9 year old transmission with a factory rebuilt one, because it couldn't be fixed or rebuilt by them. Thankfully I called Mister Transmission and Chris knew exactly what the issue was, how to fix it, and it only cost me $385 for everything and it was fixed in a day. I am so grateful that Chris and Dawn run an honest operation and provide genuinely great service. Thanks again!
Date: July 25, 2021
Website: Google
Cambridge Mister Transmission was awesome....
Sarah MacArthur
Cambridge Mister Transmission was awesome. We ended up having a small issue but they still took the time to show me where on my vehicle the problems were and fully explain the possible issues. They were prompt in getting back to me the following day and I had my vehicle back in no time. Chris and Nick were amazing and the office is so clean and pleasant. Great customer service!
Date: July 24, 2021
Website: Google
Great service , friendly and...
John Neven
Great service , friendly and very knowledgeable.Excellent work
Date: July 23, 2021
Website: Google
Mazda 3 AT light came...
Chris Elmquist
Mazda 3 AT light came on one with some bad noises and clunking. Dealer said need a new transmission for only $4400. Took it to this and a quick check they determined it needed new TCM which is very common on the mazdas. They took care of it and even did a bunch of extra work fixing a wiring harness all for the cost of the TCM . cannot say enough about how we were treated by Chris and Dawn. Would recommend them. FIRST CLASS!!!!!
Date: July 23, 2021
Website: Google
Workers are very nice and...
Ely Bolivar
Workers are very nice and explain thing clearly. Also they have an option to finance your repairs.
Date: July 22, 2021
Website: Google
They assessed the problem quickly,...
Colleen H
They assessed the problem quickly, quoted a good price, provided fast service, in a no-pressure, friendly manner. I've been telling everybodyService: Transmission
Date: July 20, 2021
Website: Google
I took my differentials down...
Kieran Massicotte
I took my differentials down to get rebuilt and Steve was very professional and the total was 200 bucks cheaper than the quoted price and there was a few things during the whole process that didn’t go as planned as I had brought all the bearings parts and some bearings were the wrong ones and I had brought 4.88s to put in end they would not work and before continuing with anything Steve would call and double check to let you know what needs to be done and get the ok from me first before they would continue overall amazing place Steve and the guys were awesome and the work was done perfect and the diffs have never been more smooth highly recommend.
Date: July 20, 2021
Website: Google
Excellent customer service.Service: Transmission
Eduardo Vieira
Excellent customer service.Service: Transmission
Date: July 20, 2021
Website: Google
Thank you Kyle and the...
Roman Danko
Thank you Kyle and the Mr. Transmission team for very professional and friendly customer service and repair. I definitelly recommend their services.Service: Transmission
Date: July 19, 2021
Website: Google
Featured Services
Transmission Repair

The evolution of transmissions has made these machines and systems increasingly complex. When transmission repairs are required, determining the cause and cure for what ails can be tricky.

Read More
Transmission Technology

At Mister Transmission we have access to leading-edge diagnostic equipment, enabling us to offer you the fastest and most accurate findings about what’s going on inside your vehicle’s transmission.

Read More
Transmission Maintenance & Service

Just as you have other parts of your car serviced, your transmission needs maintenance to ensure a long life and avoid transmission problems.

Read More
Recent Blogs
4 Common Transmission Maintenance Mistak...
Transmission maintenance is absolutely imperative to ensure long and efficient life
Read More
June 25, 2021
How A Transmission Shop Can Actually Sav...
Transmissions are expensive. And they can be expensive to fix. That’s why any visit
Read More
June 23, 2021
The Benefits Of A Transmission Fluid Cha...
When done at the right time, a transmission fluid change can really benefit your vehicle.
Read More
June 17, 2021
The Top Ten Models With Major Transmissi...
Which transmissions have the most problems? Here are the ten models with the most
Read More
June 14, 2021
“How Can I Tell What Kind Of Trans...
“What transmission do I have?” It’s a question we hear a lot at Mister
Read More
June 7, 2021
RAM Differential and Driveability Issue
You are enjoying a drive in your 2012 - 2018 Ram 1500 pickup truck and all of a sudden,
Read More
May 19, 2021
7 Common Transmission Problems
We all want to avoid transmission problems. To do that, it helps to know what some of
Read More
May 10, 2021
What Is A Driveline, And Do I Need It Se...
Have you ever heard of a “driveline” before? Wondering what it is? Does it have
Read More
May 6, 2021
Do CVT Transmissions Need Repairs More O...
CVTs are still relatively new so people often have a lot of questions about them.
Read More
May 3, 2021
Do You Really Need To Change Your Transm...
You’re supposed to change your transmission fluid every so often. But is that
Read More
April 30, 2021