Sprinter 4x4 frequently asked questions

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What vehicle variants and configurations can be converted?

An overview of vehicles with main data is given in our sales brochures. Because of the very wide range of variants and the number of possible special equipment options however, the precise vehicle configuration must be established with our sales staff in each case.

How fast can I drive in gear reduction mode?

The driving speed in gear reduction mode is not limited.

Because of the technical configuration however, in gear reduction mode driving noise rises as the speed increases, and fuel consumption and drive train load can also be higher. We therefore advise not using the reduction gear unnecessarily.

Does Oberaigner offer a front axle diff lock?

The front axle diff lock has already been completed and approved by Daimler and will be availble during 2011.

Does Oberaigner also offer the short wheelbase in all-wheel drive?

Yes, all variants are available with full ESP function and off-road options.

Does Oberaigner also offer the Super Single as all-wheel drive?

Yes.

Is the load capacity (e.g. 3.88t) retained after conversion?

Yes.

Is all-wheel drive available with petrol-engined vehicles?

Yes.

Why does Oberaigner offer ESP when others do not?

The Oberaigner all-wheel drive is based on the Daimler works all-wheel drive ? the system components of the works all-wheel drive even come from Oberaigner. Oberaigner has the licence to fit the works all-wheel drive system with ESP and also offers all off-road equipment.

This means that the Oberaigner all-wheel drive offers all modern driving dynamic control systems like the works all-wheel system (maximum safety and comfort) and also all off-road options such as diff. locks, underrun guard, etc. (maximum traction on difficult terrain).

Up to what speed can the diff locks or reduction gear be engaged?

Diffs 25 km/h, reduction gear only when the vehicle is stationary.

What is the gear reduction ratio?

1.423; from 2011, also 2.85 as an option.

Why should I not use the diffs. on dry tarmac?

The consequences of doing so are stress in the drive train, jerky steering behaviour, increased tyre wear and increased wear on the entire drive train. Also, with the diffs engaged, no brake regulating system is available.

After disabling the mechanical diffs., why do you have to turn the ignition off/on to restore the ESP functions?

This is a technical requirement for safety reasons which is imposed by the manufacturer of the brake regulator system.

What conditions must be fulfilled to be able to engage the mechanical diff or cross-country reduction gear?

Centre diff. lock:

• Engine running
• Drive speed below 25 km/h
• Steering angle less than +/- 240°
• Difference between wheel revs. < 5%

Rear axle diff lock:

• Engine running
• Drive speed below 25 km/h
• Steering angle less than +/- 240°
• Difference between wheel revs. < 5%
• Centre diff. engaged

Cross-country reduction gear:

• Engine running
• Vehicle stopped
• Brake pedal pressed
• Manual gearbox in neutral/automatic in P or N

With switchable all-wheel drive, why is there no free-wheel hub to save fuel?

Because the extra weight and loss of comfort (unsprung mass) would offset any potential benefit.

With the all-wheel drive conversion, is there more clearance between axle and road?

No, but slope angle and centre clearance are increased. Bigger wheels will give you greater clearance below the axles.

Why are the electronic brake regulator systems disabled when the mechanical diff lock is engaged?

With the diff locks engaged, due to coupling of the wheels defined brake regulation is no longer possible, and dangerous situations could occur. For this reason, it is essential for electronic brake regulator systems to be disabled when the diffs are engaged.

Does the mechanical diff. automatically disengage?

No. From a speed of 52 kph a warning tone will sound at an interval of 4 seconds.

In which situations do you need a mechanical diff. lock, and when is the 4ETS superior?

On "undefined ground" (loose surface, cross-country driving, etc.) or on smooth surfaces, pulling away with mechanical diffs is better. At high speeds however the availability of 4ETS (with full ABS and ESP function) is advantageous. It's best to have both. And you can only do that with the Oberaigner all-wheel drive.

Are spare parts only available from Oberaigner, and who pays for warranty work?

Many components are Daimler standard parts (actually Oberaigner also supplies the standard all-wheel drive) and hence available from Daimler; specific Oberaigner parts (e.g. diff locks) can be obtained from Oberaigner. Oberaigner provides corresponding documentation for professional workshops via the internet. Any warrant work is charged by the workshop directly to Oberaigner.

Which wheels can I fit to my Oberaigner all-wheel drive vehicle?

In principle, the wheel and tyre sizes given in the registration documents can be used.

Our sales brochures show you the possible wheel sizes.

How does the warranty work (who gives what warranty)?

Oberaigner gives a warranty on components it has fitted; the warranty for the complete vehicle is provided by Daimler.

Is there an extended warranty option?

The 12-month legal warranty can be extended by the registered keeper using the warranty activation form to give a further 12 months' manufacturer's warranty.

Is switchable 4x4 drive better for fuel consumption than permanent 4x4?

In our internal tests, no measurable differences in fuel consumption could be found.

Why is there no rear diff option on the 4x2?

When the diffs are engaged, all control functions must be temporarily disabled.

When all control functions are switched off therefore the EBV function is also disabled.

This has the same function as the former ALB regulator and prevents locking of the rear wheels before the front wheels. 

Depending on vehicle variant and load, without the EBV function the rear wheels could lock before the front wheels. In this state, the vehicle would not fulfil its licence conditions.

With centre diff engaged, this risk no longer exists as the rear axle cannot "overbrake". Therefore the centre diff must be engaged first, and only then can the rear diff be engaged.

Why can't you have a rear axle diff without a centre diff?

When the diffs are engaged, all control functions must be temporarily disabled.

When all control functions are switched off therefore the EBV function is also disabled.

This has the same function as the former ALB regulator and prevents locking of the rear wheels before the front wheels. 

Depending on vehicle variant and load, without the EBV function the rear wheels could lock before the front wheels. In this state, the vehicle would not fulfil its licence conditions.

With centre diff engaged, this risk no longer exists as the rear axle cannot "overbrake". Therefore the centre diff must be engaged first, and only then can the rear diff be engaged.

Why are no diff locks available on switchable 4x4?

The space available in the distribution gearbox used for the diff lock on permanent all-wheel drive is needed for the switching mechanism in the switchable all-wheel drive version.

Manual or automatic transmission?

In principle, the choice of main transmission is a matter of personal preference.

But for cross-country use, we recommend automatic as it makes driving at very low speed and pulling away considerably easier. As there is no interruption in pulling power when changing gear, the cross-country mobility of the vehicle is better.

Which axle ratio should I select?

• For use mainly on flat roads and motorways, choose lower axle ratios (reduction of engine speed => reduction in fuel consumption)
• For all other usages, choose higher axle ratios (higher traction force, slower manoeuvring possible etc.)

Under which circumstances should the reduction gear be used?

• Frequent driving in hilly terrain
• Frequent manoeuvring (reduction in clutch load)
• Vehicles with low axle ratio
• Frequent driving with heavy load on climbs
• Driving at very low speed (on "undefined ground" (scree, sand etc.), poor road surfaces, off tarmac roads)

What all-wheel variants are recommended for which area of use?

• Traction support (rain, snow) / optimised driving dynamics: permanent all-wheel drive without diff lock with 4ETS
• Steep gradients, frequent manoeuvres etc: with support
• Driving on "undefined ground" (scree, sand etc.), poor road surfaces, off tarmac roads, etc..: permanent all-wheel drive with support and diff lock(s).

Why must ESP be degraded with many tyre types?

For each individual tyre variant, ESP must be set up in all conceivable driving situations and all conceivable weather conditions at great expense. This has been done for standard tyres. For special tyres however ESP must be degraded for safety reasons.

How is the torque split when the centre diff is engaged?

In locked state, only the axle revs (centre diff) or wheel revs (axle diff) are set, and it has no effect on the torque split. The torque distribution is theoretically 50%:50%, but in reality always depends on how much torque can be transferred to which axle or which wheel. In driving mode, the split can briefly even be 0%:100% or vice versa.

A rough approximation is that with equal ground adhesion, the torque distribution corresponds to the axle load distribution.

Why is a torque distribution of 33:67 % preferable over 50:50 %?

• This torque distribution was selected because it represents the optimum in terms of driving dynamics. The vehicle drives neutrally through to slight oversteer up to the limit zone. This corresponds best to the vehicle reaction expected by the driver. This is most comfortable especially for drivers who drive both 4x2 and 4x4 vehicles.
• With this split, it's also possible to retain full ESP functionality even in all-wheel drive. Vehicles with mechanical differential locks from Oberaigner need not give up the benefits of ESP as a whole, as ESP is only temporarily disabled for safety reasons in diff. mode.
• Taking into account all variants, in particular the tonnages, this split provides the best possible traction. To achieve optimum traction, the torque distribution must correspond to the dynamic axle loads. The rear axle has a higher axle load, and when climbing and accelerating, weight tends to shift towards the rear axle. A loaded 3.5-tonner on a 30% uphill gradient for example has an axle load distribution of around 35:65.