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The differential (more commonly referred to as a diff)  is the component in your vehicle that helps the wheels of your vehicle turn. It spreads power from the vehicle’s transmission and powers the wheels enabling them to rotate at different speeds. Differentials are among the more popular products in our Ford driveline parts range.

There is at least one differential in all modern cars, SUVs, and trucks. 

The differential plays a significant role in how your car makes turns while driving. Your diff basically allows each wheel of your vehicle to spin freely independently of the other, while still providing power to all.

The differential is particularly designed to drive a pair of wheels while enabling them to rotate at different speeds. 

The diff distributes equal amounts of torque to both wheels. This gives the wheels the ability to react to resistance, or provide traction, so the wheel can have more resistance to rotate less. The wheel with less resistance will rotate faster.

Without a differential, both driving wheels will be forced to rotate at the same speed, typically on a common axle driven by a pretty simple chain-drive mechanism. 

If your vehicle has a broken or faulty differential, your driving wheels would be locked together. This is very risky because if your driving wheels are locked together, it forces them to spin at the same speed, which makes turning difficult. The resultant effect is that it increases the chances of your losing control of the vehicle. 

So technically, you can drive with a broken differential. However, as you’ve probably already figured, it’s not a wise thing to do. Driving with a broken diff only worsens the problem and can result in you getting stranded. 

It can also spread damage to other surrounding components. So it’s simply smarter and safer not to drive with a bad or broken differential.

You can tell that your diff is bad and needs servicing if:

• it makes a whirring noise only when you are decelerating.
• it rumbles or makes whirring noises at speeds over 30kph but changes while turning.
• there is a regular ‘clunking’ sound when your car starts to move.
• there is a steady vibration that increases with the speed of your Ford.
• it howls or whines when you accelerate over low or large speeds.

If you are experiencing any difficulty turning or controlling your car, that could be a sure sign that a component in this area of your vehicle is failing. 

If you need to replace your differential, we at Smart Replacement Parts have got you covered. We have a wide range of Ford driveline parts that can be shipped worldwide. Contact us for your transmission parts and full transmission replacements like a Ford AU diff centre.

The Tag Number

The bottom line of the axle tube stamp provides the most exact differential identification. Differential tag numbers can easily be used to identify your Ford differential.

Bill Of Materials (BOM) 

You can also use the Bill of Material (BOM) number to identify your Ford differentials. The BOM identifies the model number, the type of differential, the gear ratio, and all other component parts. 

If the identification tag or stamp is missing or you can’t read it, you can identify your diff type by the number of cover bolts, the distinctive shape of the cover,  the ring gear diameter, and the number of ring gear bolts. 

If you still think you need help with identifying your differential, you can reach out to our team of experts. 

The differential is a simple mechanical device, and so there are a few problems that can cause damage to it or make it go bad. 

The first and most common cause is the absence of differential oil. This can cause the gears inside the differential housing to break, grind, and even block the rear wheels. 

This loss of oil can happen for several reasons. It may be because the differential seals are worn and leaking or that you hit the differential housing, causing the oil to drip.

However, differentials can also go bad if you push them too hard. This happens if you’ve performed too many burnouts, street or drag racing, and so on. The diff can also go bad if you frequently take an unsuitable vehicle through rough areas. 

Also, you should know that differentials can break if the inside gears are made of soft quality steel that’s unable to withstand engine power and torque. 

Plus, if you don’t change the oil or service your differential regularly, you are setting it up to go bad. You should get your differential fluid (gear oil) changed after every 50,000 – 90,000 kilometres by a trained technician. 

When your differential oil is clean and fresh, it protects your differential better and ensures that you have a safer ride. Like any other component of your Ford, well-lubricated parts will result in optimal performance.

Both a Limited Slip differential and an Electronic Locking Rear differential can maximise the available torque to the wheel or wheels with the most traction. Still, they do this in different ways and have different applications.

The key feature that a locking differential has is its ability to force both of the drive wheels to actually rotate at the same speed, notwithstanding traction needs. We have excellent locking differentials in stock, including the Ford M86 diff (which is also available as a single spinning type) and the Ford BA Ute diff.  

The electronic locking differential has its benefit when one of the wheels slips. The differential will continue to keep sending torque to both wheels equally. The wheel with traction will then provide motion.

On the other hand, the limited slip diff allows the wheels to continuously turn at different speeds without locking to each other completely. This can restrict the amount of torque that the spinning wheel gets and maximise the torque that is sent to the wheel with the best traction. 

Most sports cars use the limited slip differential. They are also common in all-wheel-drive vehicles.

The electronic locking differential allows both rear wheels to turn at the same speed and provides additional traction if your vehicle becomes stuck. You activate the diff electronically and shift it on the fly within the operating speed range. 

The electronic diff disengages when the vehicle speed goes beyond a set value, and re-engages when the vehicle speed falls below a set value. It also engages based on the selected drive modes. 

It would be best to use the electronic locking differential in mud, rocks, and off-road conditions where you need maximum traction. It’s not advisable to use it on dry roads.