gearbox repairs

The Gearbox section of your vehicle is known as the brain. If the engine is the heart of a vehicle, then the gearbox is most certainly the brain. 

The gearbox (brain) is to ensure your vehicle moves or drives. Without it the engine (heart) has no function. That is why it is very important to look after and service your gearbox. 

The first part to fail will be the bearings in the gearbox.  The oil will lose its viscosity and become like water.  The bearings cannot lubricate properly and will get hot. This causes gear float in the box.

This basically means the gears that drive the vehicle forward start to shift and rub up against each other, causing a chain effect. The Gearbox will jump out of gears because the hub and sleeve are not able to engage and hold the gear in place. The gears will start grinding because the brass synchro’s wear down from the movement. The synchro’s job is to stop the gear mid change so that the hub and sleeve can engage. This all happens in split seconds. 

And there you have a chain effect. 

Then the selectors, which are made of aluminum, also wear away from the movement and that is why you struggle to engage the gears. 

All these moving parts are the soft parts in the gearbox and usually go first. Once the hard gears start to break a major gearbox repair will need to be done or if left longer a complete reconditioning of the gearbox will be inevitable.


Important Signs Your Gearbox may be failing

Do not ignore the signs that you are having problems with your car, especially if you want to avoid those nasty repair bills. The gearbox is one part you do not want going wrong as it is one of the most expensive parts in your car. Problems with your gearbox can be fatal so being vigilant is vital. 

Below is a simple guide to help identify that something is not quite right in the world of your gearbox.


Dashboard Warning Lights

Keep an eye out for the transmission temperature light indicating that the fluid in your transmission is operating at a higher temperature. Check your coolant and transmission levels regularly to ensure the systems are properly topped up. While this light may not be a transmission fault and could even be outside of the gearbox, it is important to get any potential problem checked out by a professional mechanic.


Leaking Fluid and Low Levels

This is possibly the easiest symptom on the list to spot. All you have to do is check for leaks, by placing a few old pieces of paper or cardboard under the car. You are looking for the tell-tale red colour of transmission fluid, which also has a slightly sweet smell. Unlike motor oil your transmission fluid levels should stay constant so any signs of this fluid under the car are indicative of a leak.

To perform the fluid checks, run your car for a short time in neutral before pulling out the dipstick without turning your engine off. Get a little of the fluid and rub in between your finger and thumb or use a white paper towel or toilet paper and drip the liquid onto the material to highlight the colour.

In order to ascertain the levels, insert the dipstick, wipe clean and insert again. Now pull it out and you’re looking for a mark between the full and add lines. If the level is below the add line it’s a simple instruction to add more fluid. Check your owner’s manual to get the right fluid and be careful to add the right amount of fluid. If you are unsure, add a little at a time and re-check levels.

If you check the fluid levels and they are lower than expected the chances are you have a leaking system:

  • Sign of a clogged filter or loose plug
  • Worn seals or gaskets
  • Worn axles on a front wheel drive vehicle
  • Problems with engine and transmission mounts
  • Damaged bell housing
  • A loose transmission pan or pan leak
  • Drive shaft out of balance


Smells and Odours

Light smells and burning odours leaving a sweet and tart fragrance in your vehicle may indicate it is time for you to change the transmission fluid. If the fluid is not keeping the system properly lubricated then it is time for a change to prevent the unit from burning itself up. When you check on the transmission fluid if it has a burnt smell then it may be a sign that your gearbox is nearly finished. Get it checked out by a professional quickly to avoid some serious damage and costs.


Audible Noises

If there are banging or clanking noises  however while the car moves into neutral then this is a good indicator that there may be loose gears and parts in the clutch. The worse the sounds are, the looser the parts, the greater the chance of damage.

Be wary of whistling and clicking noises, which may be an indication that your gearbox’s bearings are becoming worn and that you may be looking at a replacement gearbox. Abrupt and jarring grinding sounds when shifting gear may mean you have worn out the clutch or the synchronisers may be damaged.

With automatic transmissions you will feel those gear changes instead of the smooth shift, but there is also a good chance that you will hear a whining, buzzing or humming sound. This could be a problem with the torque convertor.


Out of the Ordinary Behaviour

You know your car and how it handles. If the gear starts changing for no reason, such as if you’re out on the open road and your manual gearbox shifts into a different gear or it slides into neutral in an automatic, you have a problem with the shifting. Another tell-tale sign to keep on ear out for is a whine or accompanying pitch shift from the engine.

Also delayed engagement of the gearbox is another symptom that should not be avoided. Does your car take a little time before going into drive and going forward? If you have already pushed the clutch down and brought it up to the biting point, but it still takes time to go then this is a sign the part is on its way out.


And finally

Identifying problems with your car isn’t always easy, even for well-trained mechanics. Remember that if you think something isn’t quite right then you should go and see a mechanic straight away rather than leaving the fault until it becomes an expensive problem. Any indication that your car’s gears are not working properly is a good enough reason to get into the garage. Make sure to get your car checked out before further damage occurs or you find out what a failure is like on the open road.

If picked up early an entire Gearbox repair can be avoided.

To prevent gearbox repairs or replacement gearbox services and oil changes are vital.