Drive and RestoreSelespeed and Dualogic explained: how they work and what goes wrong
Selespeed and Dualogic look like automatics from the driver’s seat, but underneath they are something else: a normal manual gearbox and clutch, operated by a robot. That gives them a sporty character and good economy, and it also explains their weak points. Here is how they work and what to watch for.
Same idea, different names
The system was developed by Magneti Marelli. Alfa Romeo called it Selespeed, Fiat called its version Dualogic, and Lancia used the name D.F.N..
The Alfa Romeo 156 introduced Selespeed in 1999, the first car in its class with this type of robotised gearbox. It was later offered in the 147, GT, 159, Brera and Spider, and the related systems went into Fiat models such as the Punto, Stilo and 500, and Lancias such as the Ypsilon and Musa. Similar technology was used in the Ferrari 355 F1 of the same era.
How it works
At its heart is a conventional manual gearbox with a conventional single-plate clutch. What replaces your left foot and right hand is an electro-hydraulic unit:
- an electric pump builds up hydraulic pressure, stored in an accumulator;
- an actuator with solenoid valves uses that pressure to operate the clutch and move the gear selector;
- a control unit decides when and how to shift, using sensors for gear position, clutch position, engine speed and road speed.
The driver changes gear with the lever or paddles. Early 156s had buttons on the steering wheel; paddles came with the 147 and the facelifted 156 in 2002. There is also an automatic mode (City), and downshifts are rev-matched automatically.
What goes wrong
Most problems come from the hydraulics and the sensors, not the gearbox itself:
- “System failure” warning light. The main early sign of trouble. Sometimes it is just a faulty paddle switch, but it can point to something more serious, so have it read out.
- Pump. Clicking, clunking or a long priming time before a gear can be selected can mean the pump is failing.
- Actuator. Slow or hesitant shifts, especially when cold, point to actuator wear.
- Clutch position sensor. A faulty sensor gives rough shifts or gears that won’t engage.
- Leaks. Hydraulic fluid leaks mean failing seals.
- The clutch. It is a normal clutch and it wears like one. After a clutch replacement the system has to be recalibrated with diagnostic equipment so it learns the new clutch’s bite point.
Looking after one
- Fluid. The system uses a specific hydraulic fluid that degrades over time. Use exactly the specified fluid and change it on time: the interval often quoted for Selespeed is every two years or 20,000 miles, and some specialists recommend more often on high-mileage cars.
- Cold starts. Give it a minute after a cold start before pulling away, and shift gently until it is warm.
- Don’t ignore the warning light or changes in shift quality. Small problems become expensive ones.
Buying a car with Selespeed or Dualogic
On a test drive, check that:
- it downshifts by itself as you slow down;
- it never changes gear randomly, slips, or struggles to find a gear, including neutral;
- it doesn’t take long to prime before you can select a gear.
If any of these fail, walk away or budget for a repair. Ask for service records showing fluid changes and any actuator or pump work.
Repair or replace?
Dealer quotes for a complete new unit can be high. Independent specialists can often repair or recondition pumps and actuators, and when parts are needed, the original part number is the key to getting the right version: there are many variants across models and years.
Sources
- Wikipedia: Selespeed
- Garage Dreams: living with a 147 Selespeed, a survival guide