What is a Sequential Gearbox, & How Does It Work?

High-performance race cars have unique gearboxes that enable them to pick up quickly and is called sequential gearbox. This kind of gearbox is similar to the manual gearbox with some slightly different features and functionality. This guide will teach you what a sequential gearbox is and how it works.

What is a Sequential Gearbox?

Have you ever ridden a motorcycle? In a motorcycle, you shift gears by slightly pressing the gear lever, either up or down, depending on the type of motorcycle. Slightly pressing up and down or clicking the gear lever is the fastest way of shifting gears. A sequential gearbox will let you change gears by clicking the gear level up or down. 

In a sequential gearbox, you will shift gears manually. Though there is an order you must follow, it does not allow you to skip gears like the manual gearbox. The gear selection is unique to the transmission type. You can either up or downshift.

How a Sequential Transmission Works

You understand how sequential transmission works better if you have a basic understanding of how manual transmission works. The five-speed manual transmission gearbox is popular in the automotive industry. 

You will realize that the manual transmission has three forks controlled by three rods. On the outer part, you will see a gear shifter lever connected to the three rods. It is the gear lever that engages the three rods whenever you shift. 

When you look at the shift rod from the top, you will tell what the gears look like in neutral, reverse, first, and second gear. From this is an ‘H’ pattern that enables you to shift smoothly between the control rods of the three forks. You can thus move the rod freely back and forth.

The sequential gearbox works similarly. It has gear selector forks moving the collars to engage and disengage the gears. The difference comes in the manipulation of the control rods. Instead of the ‘H’ pattern, it has a different motion.

In race cars, you can shift the lever by pushing it forward or pulling it backwards and Up or down. Pushing the shifter forward lets you move to a higher gear, for example, from 2 to 3. If you want to drop the gears from 3 to 2, you only need to pull the gear lever backwards.

The formula One car has two paddles on both sides of the steering wheel. The left paddle shifts up while the right pedal shifts downwards. A motorcycle has only a single shifter that you can pull or push to change gears. The difference is that you will do everything with your foot. 

The up and down or pull and push motion aims to rotate the ratcheting drum. Moving the lever increases the rate at which the drum rotates. The rotation initiates the rods to move as per the grooves in the drum as you change the gears.


The working principle of a sequential gearbox is almost similar to the manual gearbox. In both, you will shift the gears by touching the shifter. The difference is that you can skip the gears in the manual gearbox, but this is impossible in a sequential gearbox. You have to move from one gear to another. Such a sequence is the origin of the name sequential. 

Best Way To Check And Refill Gearbox Oil in a Truck

Wondering how to check and refill gearbox oil in a truck? The engine and the transmission system are composed of metallic parts. It is the movement of these metals which makes the wheels of your truck move. The most important part of your truck is the gearbox. The gearbox has various gears made of metals. The gearbox needs oil to function smoothly. 

Overview Of Gearbox oil

The gearbox oil lubricates the transmission system. The primary role of the gearbox oil is to lubricate the gears and ensure that the entire transmission system is running smoothly. The gearbox oil protects the internal part of the transmission system from tear and wear, which can damage them with time. If the level of your gearbox oil is low, the moving metallic parts of the transmission system will not be able to receive adequate lubrication, and this might damage such parts.

Various factors result in the reduction of the levels of the gearbox oil. When your truck has less gearbox oil, you will feel the gears jerking, and gears will slip, shifting problems, as well as strange noises. The gearbox oil should not drastically drop below the required levels. If such happens more often, consider checking for leakages along the transmission system. 

How To Check and Refill Gearbox Oil in a Truck

Never let your truck run on low gearbox oil. To ensure that the levels of oil in your transmission system are standard, do the following to check and refill your gearbox oil.

  1. Park your truck on plain ground and engage the handbrake. The gear lever should be neutral or parking. Start your engine and let it run to warm the oil to enable you to get the current dipstick readings.
  2. As your engine runs, open the bonnet and locate the dipstick. You will find it in the rear compartment of your engine. In some trucks, you will see the filter plug, which functions as an oil level dipstick.
  3. Pull the dipstick out carefully because the oil might be hot, then wipe it. Reinsert the dipstick and then remove it to read the marking of oil at the end of the dipstick.
  4. The dipstick has lower and higher markings showing the gearbox oil levels. The level of oil should be close to the upper mark.
  5. Observe the color of your gearbox oil. Healthy gearbox oil should be slightly red and not have any burning smell. If it is dark, consider changing it.
  6. If your oil levels are low, use a long neck funnel and refill the recommended gearbox oil up to the recommended levels. Do this with the dipstick inside to enable you to determine the proper levels of oil. You should not refill the oil beyond the recommended mark. 
  7. Remove the funnel together with the dipstick. Check if the levels of the oil are okay. Insert the dipstick and close your bonnet.


Gearbox oil is the backbone of your gearbox. To give your truck long life, consider checking the levels of this oil regularly and topping it up whenever it is low. Shared in this guide is how to check and refill gearbox oil in a truck. Checking the oil will enable you to determine whether it is healthy.

Manual Gear Jumps – Top Causes of Manual Gear Jumps

Among some of the issues experienced in manual vehicles is manual gear jumps. It is fun to drive a truck with a stick shift. Driving a manual transmission truck brings a lot of joy, but the bad news is that they are getting fewer on the roads today. Apart from becoming extinct, a few mechanics can work on such transmissions, which raises the question, what causes the manual transmission truck to jump out of gears? After reading this guide, you can have an adequate answer to this question.

Causes of Manual Gear Jumps

The manual transmission can jump out of gears for several reasons, such as worn-out mounts or loose linkage. When the shifter bearing is faulty, you will likely experience this problem. Below are more detailed reasons why your manual transmission truck will jump gears.

Internal Failure

The manual transmission has various internal components which can fail when poorly handled or old. When your transmission keeps popping gears, it might have a more significant problem, like the shift folk assembly or the synchronizer.

If the synchronizer is faulty, the transmission will pop some gears. You will also experience difficulty when downshifting gears. If your gears are worn out, consider replacing them.

Weak Spring in Shift Rail

The springs are located inside the shift rail. Its primary role is to lock the transmission into gear. The springs break when they are weak, and you will notice trouble if this happens.

The shifter ball will slip out when the springs break. If the shifter makes an unexpected motion, your transmission will slip gears.

Faulty Shifter Bearing

The shifter has surrounding it, and sometimes, they become worn out or faulty, making it difficult for the gear lever to engage the gears adequately. When you feel your shifters are loose, the bearings around you are worn out. 

The gears will slip when they are not pressed well against each other. In such a scenario, your truck will drop into neutral as your drive. 

Loose Linkage

The linkage rods of your truck become loose as it gets old. The rods connect the gear shifter to the transmission. When it becomes loose, it becomes difficult for the transmission to become locked in the gear.

When the transmission mount is worn out, the linkage will stretch out. 

Worn Mounts

The transmission mounts wear out over time. If this happens, the transmission will move whenever your truck accelerates. If there is a lot of motion on the transmission, the shift linker will move too much, stretching the cable.


To solve the problem of manual gear jumps in your truck, you can adjust the transmission. Adjusting the transmission varies depending on the model of your truck. You should refer to your service manual or consult a professional mechanic to perform this procedure effectively. 

For you to solve the issue of manual gear jumps, it is necessary to know some of its causes. This guide has focused on the most common causes of manual gear jump, which you should know as long as you own a manual transmission truck.