Torsen quattro differential service is something worth understanding if you drive an Audi with this legendary four-wheel-drive system. quattro with Torsen is the system that helped Audi build its reputation. On models with a longitudinal engine – A4, A5, A6, A8, Q5 and Q7 – the centre differential is mechanical. It distributes power between the front and rear wheels without relying on electronics. Tough, reliable and built to last. But here's the thing! That doesn't mean it'll last forever. Especially if you forget about the oils.
How does Torsen quattro work?
On these models, the Torsen differential sits at the back of the gearbox. The front diff is also inside the gearbox, while the rear diff is a separate unit on the rear axle. All three need oil to do their job. But that oil doesn't stay fresh forever. Over time, it works hard, ages and loses its ability to protect the moving parts.
Which oils need changing?
- Gearbox oil – on S tronic and manual gearboxes, there's often separate oil for the gears themselves.
- Rear differential oil.
- On some versions, the front differential has its own separate oil too.
Not every quattro system is the same. That's why we check the gearbox code to identify exactly which drivetrain your car has and which oils it needs.
When should you change the oils?
In the manufacturer's service schedule, some of these oils are described as "lifetime" fluids. But I don't believe in oil that lasts forever. As the miles add up, the oil loses its protective properties, and the gears and bearings start wearing out faster. That's when things get expensive.
That's why I recommend changing the rear differential oil and the oil that lubricates the gears earlier than the factory schedule suggests. Especially if your car has covered a lot of miles, you tow a trailer or you enjoy putting your foot down. Changing the oil in good time makes far more sense than paying for a differential repair.
How can you tell something's wrong?
- You hear a whining noise from the rear that changes with your speed.
- You notice oil leaking around the differential or driveshafts.
- You hear clunking noises when pulling away or turning.
Don't drive your quattro with tyres that differ in size or wear. That makes the wheels rotate at different speeds, puts extra strain on the centre diff and can damage it. I'm telling you this because, if it goes wrong, you're the one paying for the repair.
Advice from Kris Mladenov: On a quattro, change all four tyres together. If you fit new tyres at the front but leave the old, worn ones at the rear, you're just putting unnecessary strain on the drivetrain. It's really not worth it.
If you drive an Audi with Torsen quattro and can't remember when the oils were last changed, come and see us at Das Auto Service. We'll identify exactly which drivetrain your car has, check its condition and work out which oils need changing. No throwing parts at the problem and hoping for the best.
What you'll find in our shop
Genuine differential oil 1 litre
Genuine differential oil, the same oil we use when servicing the rear axle.
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Genuine gearbox oil for S-Tronic dual-clutch gearboxes G052529A2 1 litre
Genuine S tronic oil for models fitted with this gearbox.
View in our shopRead more
- Gearbox servicing
- Routine servicing at Das Auto Service
- Haldex generations 1 to 5: when and how should you service them?
- S-tronic 0B5 (DL501): mechatronic unit, clutch and two oils
- Audi RS gearbox oil change: how we do it
Frequently asked questions
Do you need to change the differential oil on a quattro?
Yes, my friend. As far as I'm concerned, there's no such thing as oil that lasts forever. Especially once your car has covered a fair few miles.
Why do all four tyres on a quattro need to match?
Because different tyre diameters make the wheels turn at different speeds, putting extra strain on the centre differential. That's why you shouldn't fit new tyres on one axle while leaving worn ones on the other.
How can I tell if my rear differential has a problem?
The most common sign is a whining noise from the rear that changes with your speed. You might also notice oil leaking around the differential.