Traction with brains: vans with all-wheel drive

Aug 2, 2011
  • Sprinter 4x4: the van for everyone, thanks to numerous variants
  • T2 and Vario 4x4: the all-wheel drive for professionals
  • Vito 4x4: compact van with off-road vehicle traction
Whether it’s construction engineers or power line technicians, water supply engineers or the rescue services, council workers or disaster protection agencies, delivery drivers or mountain resort hotel staff – none of them can choose the spot where they are needed and they often have to get there under the most difficult of circumstances. Extreme gradients, rough terrain, badly eroded tracks, saturated fields, ice and snow are just some of the obstacles that have to be overcome. Outstanding traction is indispensable in such cases. This is where the Mercedes-Benz Sprinter 4x4, Vario 4x4, Vito 4x4 and Viano 4MATIC came into their own. No other van manufacturer produced such a wide range. Private purchasers also benefited, for example, if they were looking for a camper offering particularly high traction.
Sprinter 4x4: the van for everyone, thanks to numerous variants
A former military training area not far from Berlin provided the venue. In spring 1997, Mercedes-Benz had given motoring experts an off-road demonstration of an all-wheel-drive van. The Sprinter, which had been introduced for the first time just two years previously, was then able to display its outstanding ability to cope with rough terrain. Its predecessor model, the T1, also known as the ‘Bremer’ because it had originally been manufactured in Bremen, had already been skilfully converted from a classical rear-wheel-drive vehicle to an all-wheel-drive van with particularly strong traction. The preferred solution for these individually produced vehicles was the immaculate all-wheel technology employed in the legendary Mercedes-Benz G-Class. But this saw the introduction for the first time of a professionally developed factory design.
The Sprinter fitted the bill perfectly: rear-wheel drive, a turbodiesel producing for its time an amazingly powerful 90 kW (122 hp), plus a very extensive range of models. All in all, an outstanding basis for a 4x4 van, which was quite deliberately not a replacement for an off-road vehicle but which could be a tremendous aid to professional users in all sorts of situations.
All-wheel drive, manually selectable up to 20 km/h
The central feature of this version was the re-designed all-wheel drive which, at the touch of a button, could be manually selected and deselected while driving at speeds up to 20 km/h. With front axle drive selected, the torque was distributed in a 50:50 ratio between front and rear axle. For safety reasons, the front wheel drive automatically deactivated when the engine was switched off. As a consequence, the Sprinter 4x4 could never inadvertently be started up with front-wheel drive selected, even if the selector switch was set to ‘all-wheel’.
Extra weight amounts to around just 130 kilograms
The additional components for the 4x4 drive weighed around 130 kilograms, a favourable figure compared with the permissible gross weight of a full-size van. Installing the additional components also raised the ride height at the front axle by 110 millimetres and by 80 millimetres at the rear axle. Modifying the front axle reduced the steering angle from 46 to 36 degrees, producing a larger turning circle.
The exemplary safety engineering features were already typical of the Sprinter by this time; it was the first van of its class to be equipped as standard with an anti-lock brake system and disk brakes all round. Selecting front-wheel drive automatically switched off the ABS functions; they would be re-activated in the same way by reverting to 4x2 drive mode.
Optional manually selectable gear ratio
Depending on the variant, the angle of approach ranged from 31 to 35 degrees. The ramp angle, depending on the wheelbase, measured between 20 and 26 degrees. The first generation Sprinter 4x4 was able to satisfy particularly demanding traction requirements by an optionally available, manually selectable transfer box gear ratio of 1:1.4. A manually selectable differential lock on the rear axle was also available as an optional extra; the longest wheelbase variant was equipped with this as standard. All the all-wheel-drive components were housed within the floor assembly, providing them with maximum protection against external damage.
An extensive model range to satisfy the most varied requirements
An extensive model range was typical of the Sprinter, and essential for professional use in the 4x4 segment. One Sprinter version, for example, was powered by a five-cylinder diesel engine, capable of delivering 90 kW (122 hp) from a cubic capacity of 2.9 litres and achieving a high maximum torque of 280 newton metres – an important tractive power bonus, particularly off-road. An alternative was provided by a 105 kW (143 hp) four-cylinder gasoline engine, producing torque of 210 newton metres from a cubic capacity of 2.3 litres. The range was later complemented by a 74 kW (100 hp) five-cylinder turbodiesel engine.
Power transmission was achieved by either a mechanical five-speed manual transmission or a fully automatic transmission. A choice of up to four axle ratios was available for all versions.
The vans were available as cargo vans, crew buses (either normal or high roof versions), as platform trucks, stripped chassis or double cab in any of three wheelbases and, as required, with a permissible gross weight of either 3.5 or 4.6 tonnes.
The Sprinter with permanent all-wheel drive follows in 1999
One year after introducing the Sprinter 4x4, Mercedes-Benz extended the range by adding a variant with permanent 4x4 drive. This variant’s power distribution between front and rear axle was in the ratio 35:65.
In the following years the Sprinter 4x4, like its sister models with rear-wheel drive, benefited from continuous and extensive product enhancements. Particular examples were the introduction in spring 2000 of powerful and fuel-efficient CDI diesel engines with ratings of up to 115 kW (156 hp) and producing 330 newton metres of torque. As well as receiving a visual makeover, the Sprinter was also given a new cockpit and a joystick gearshift – to save space; the gearshift lever was moved to the instrument panel for easy reach.
The automated six-gear ‘Sprintshift” transmission replaced the optional automatic transmission. And, at the same time, the differential lock on the rear axle in conjunction with all-wheel drive became standard equipment for all models. Another model refinement in 2000 was further development of the automatic brake differential (ABD) to produce a fully-fledged traction control system (TCS). Two years later, Mercedes-Benz introduced the ESP® Electronic Stability Program. In 2000, the Sprinter with all-wheel drive demonstrated its abilities when it was used as the support vehicle for Hubert Schwarz, the ultra-distance sports cyclist. The Sprinter 4x4 accompanied him on his cycle journey around the world.
The new 2007 model Sprinter 4x4
After eleven years and with well over a million vehicles produced, the successful earlier model was replaced by a new Sprinter in spring 2006. That same year, a prototype version with all-wheel drive was shown at the 2006 International Commercial Vehicle Show. It was launched on the market in spring 2007. The new model offered permanent all-wheel drive which, under normal driving conditions, distributed power in the ratio of 35:65 between the front and rear axles.
4x4 and 4ETS: a unique world-beating combination
Instead of mechanical differential locks, the all-wheel drive now operated with the 4ETS Electronic Traction System. This system automatically and individually applied braking force at short intervals to any one or more wheels that lost traction. At the same time, the drive torque was transferred to any wheel or wheels still having sufficient grip. With the new Sprinter 4x4, the all-wheel drive operated even more effectively because 4ETS was integrated into the standard ESP® and specially adapted to the all-wheel drive. The effect of the interaction between 4x4 and ESP® was that the vehicle could be controlled with supreme ease at all times within its physical limits and kept safely on course.
Like its predecessor, the Sprinter was raised by 110 millimetres at the front and by 80 millimetres at the rear. Depending on the model, the angle of approach was 27 to 28 degrees (50.95 to 53.17%); and the angle of departure of the closed body variants between 12 and 27 degrees (21.26 to 50.95%). Compared with the conventionally-powered model, its ability to cope with steep gradients improved by up to 20 per cent. At a maximum speed of 20 km/h, its fording depth was 620 millimetres. The additional weight of the all-wheel drive was limited to between 115 and 135 kilograms, depending on the model.
Sprinter 4x4: more choice than ever before
The Sprinter 4x4 was available in numerous bodywork, length and weight variants. In practice, this meant a choice of three wheelbases, four body lengths and three roof heights, and of permissible gross weights between 3.5 and 5.0 tonnes. Propulsive power was delivered by four-cylinder and six-cylinder CDI engines with power ratings of 80 kW (109 hp), 110 kW (150 hp), and 135 kW (184 hp). There was a choice between the standard six-gear manual transmission and a five-gear torque-converter transmission, plus various axle ratios so that the vehicle could be perfectly tailored to individual operating conditions. Like its predecessor, the Sprinter 4x4 would also be available later on with a manually selectable all-wheel drive and a similarly manually selectable 1:1.4 reduction for particularly demanding working conditions.
The Sprinter 4x4 also benefited overall from the van’s model change. Large 16-inch wheels increased both traction and ground clearance; they also provided space for a particularly lavishly sized braking system. The new cockpit gave both driver and assistant driver more room, and its exemplary ergonomic design and generous stowage facilities were highly attractive features. The safety equipment was unrivalled. In addition to the anti-lock brake system and individual airbags, at its core was the Adaptive ESP®, the latest generation Electronic Stability Program with load distribution and centre of gravity recognition.
In model year 2011, the Sprinter 4x4 fell back on the unchanged tried and tested 4ETS Electronic Traction System with automatic force distribution between the wheels. All-wheel drive could be switched in via a dashboard button if needed, either with the vehicle stationary or moving slowly at a speed of 10 km/h or less. The Sprinter 4x4 was optionally available with a reduction gear that reduced the maximum speed in each gear by 42 per cent, increasing pulling power by the same value accordingly.
The Sprinter also benefited from the torquey, smooth-running CDI diesel engines, also introduced in 2009 and having an output ranging from the four-cylinder engine delivering 95 kW (129 hp), to the V6 engine producing 140 kW (190 hp). All were equipped as standard with a particulate filter, meeting the Euro 5 exhaust gas standard, and optionally even the strictest emission standard of the time, the (voluntary) EEV level (Enhanced Environment-friendly Vehicle). Power transmission was via the especially economical 6-speed manual transmission, also introduced in 2009, or a comfortable automatic transmission. Two weight variants with a GVW of 3.5 and 5.0 tonnes met every possible transport requirement.
T2 and Vario 4x4: the all-wheel drive for professionals
Over many years, Mercedes-Benz large-capacity vans have earned a unique reputation. They are the number one choice of the construction industry, the rescue services and council workers and of skilled tradesmen, whenever they are looking for a sturdy van, easy to operate and with a high payload in the region of up to 7.5 tonnes gross weight. They also offer a suitable and serviceable basis for midi buses and special bodies.
An all-wheel drive, of the sort which Mercedes-Benz has been supplying for many years, fits easily into this framework. Whereas all-wheel drive on the lighter Sprinter will largely be called upon to occasionally improve its traction, the Vario and its predecessor, the T2 model series, is used by a wide circle of customers in the commercial and municipal sector who frequently need all-wheel drive.
Permanent all-wheel drive part of the range since 1991
The all-wheel era began in 1991 with the 814 DA model of the T2. This sturdy, large-capacity van was equipped with permanent all-wheel drive, with short axle ratios to increase tractive power and with an additional reduction in the transfer box (on-road: 1.037; off-road: 1.67). The three-shaft VG 550 transfer box was located separately from the manual transmission and distributed some 25 per cent of the torque to the front axle and 75 per cent to the rear axle. Under extreme road conditions, the interaxle differential in the transfer box could be locked up. This produced a rigid connection between the front and rear axles. Off-road gear, inter-axle differential lock, and the optionally available rear axle differential lock were all actuated via air valves.
The vehicle was powered by the OM 364 LA diesel engine, a supercharged four-cylinder in-line engine with direct injection, one of the most recent successors to the legendary 300 engine series. The four litre capacity power pack delivered 100 kW (136 hp) and achieved maximum torque of 408 newton metres. Power transmission was delivered via a five-speed transmission with mechanical gearshift.
High-strength steel grades for the frame, large tyres
The chassis frame was designed to withstand off-road stresses by employing high-strength materials. Size 9.5 R 17.5 tyres instead of the usual 205/75 R 17.5 format increased the chassis ground clearance. Standard tyres were retained for the cargo van; either 215/75 R 17.5 or 8.5 R 17.5 tyres were used.
The all-wheel van produced in the Düsseldorf plant was available either as a stripped chassis with cab or cowl, or as a cargo van. It had a 3,150 or 3,700 millimetres wheelbase and a permissible gross weight of 7.49 tonnes. To the large-capacity van’s permissible gross weight of 7.49 tonnes could be added a 2.4 tonnes towing capacity. With a compressed air-braked trailer, the all-wheel-drive van could tow up to 7.5 tonnes. The permissible gross van/trailer combination weight then amounted to 14.99 tonnes.
Excellent traction even under difficult conditions
The T2 4x4 had disk brakes at the front and drum brakes on the rear axle. An anti-lock braking system could be had on request. Whenever the ABS control system was activated, the inter-axle differential lock in the transfer box was automatically switched off. The 814 DA all-wheel-drive van had excellent traction characteristics even under the most difficult road conditions, achieving a hill-climbing ability of 73 per cent (36.13°) fully laden without trailer and of 32 per cent (17.75°) with a trailer in tow.
Euro-2 engines offer greater tractive power
Four years on and T2 production had been moved from Düsseldorf to Ludwigsfelde near Berlin. The all-wheel-drive version of the large-capacity van had also benefited from engines redesigned to comply with the Euro 2 emission standard. Its rated power had risen modestly to 103 kW (140 hp); more importantly, its tractive power was now 500 newton metres at low engine speeds of between 1150 and 1500 rpm.
The Vario 4x4 embarked on its career in 1997
The Vario succeeded the T2 in 1996. One year later, it would be followed by the new 814 DA and 815 DA 4x4 models. Many elements of the well-tried preceding range were adopted, including the two wheelbase variants, the cargo van with two different roof heights, the platform truck and dump truck, and the chassis with either just the driver’s cab or with crew cab. The permissible gross weight remained unchanged at 7.5 tonnes and even 8.2 tonnes for the chassis version. Depending on the version, the Vario’s new OM 904 LA turbodiesel direct injection engine delivered either 100 kW (136 hp) or 110 kW (150 hp) from a cubic capacity of 4.25 litres. The high maximum torque of 520 or 580 newton metres was achieved at engine speeds of between 1200 and 1500 rpm.
As before, power was transmitted continuously to the front and rear axles via a five-speed manual transmission and the
Mercedes-Benz VG 550 transfer box. Due to the Vario’s axle load distribution, torque was distributed between the axles in the ratio of 28:72. The transfer box ratio was 1.037 on-road and 1.67 off-road. The appropriate gear ratio was selected by a rocker switch while stationary. With its two optional axle ratios, and depending on the operating conditions, the Vario 4x4 could achieve a top speed of 99 km/h and a hill-climbing ability of up to 73 per cent (36.13°) without a trailer.
Two manually selectable differential locks
In addition to the manually selectable inter-axle differential lock, a similarly manually selectable differential lock on the rear axle was then included as standard on the Vario. Both were actuated by air valves. To assist off-road mobility, the Vario 4x4, like its predecessor, ran on 9.5 R 17.5 tyres (4x2 version: 205/75 R 17.5). This increased the ground clearance below the rear axle by 38 millimetres to 216 millimetres.
High payload and a huge towing capacity
The extensive engineering content in the drive system and chassis increased the curb weight of the Vario 4x4 compared with the initial design by around 600 kilograms. Despite this, even when compared with conventionally driven vehicles, its payload was substantial, up to 3.9 tonnes in the case of the all-wheel-drive platform truck, for example. If the permissible load capacity was still not sufficient, then the Vario 4x4 was ideally suited as a towing vehicle. The all-wheel-drive van could tow up to 7.5 tonnes, and the permissible van/trailer combination weight was now 13 tonnes. At this weight, the large-capacity van could surmount gradients of up to 44 per cent (23.75°).
Whereas four internally ventilated disk brakes were fitted to the new rear-wheel-drive Vario, the rear axle of the Vario 4x4 was equipped as before with drum brakes. The background to this was the danger, particularly with dump trucks, that stones might collect between wheel and brake disk and damage the disk.
In 2003, the Vario 4x4 was given a new top-class engine, together with a six-gear manual transmission. A 130 kW (177 hp) version expanded the range into new areas. Its most impressive feature was the maximum torque of 675 newton metres.
Vario 4x4: a unique large-capacity van with all-wheel drive
Ten years after their first appearance, the Vario and Vario 4x4 benefited from an extensive upgrade in spring 2006. The main element was the installation of BLUETEC engines complying with the Euro 4 emission standard. The all-wheel-drive Vario was now available in three engine variants: 95 kW (129 hp), 115 kW (156 hp), and 130 kW (177 hp). All models were now equipped as standard with a six-gear manual transmission.
The all-wheel model, too, now had disk brakes on the rear axle. Depending on the wheelbase (now either 3700 or 4250 millimetres), the Vario 4x4 ran on size 9.5 R 17.5 and 215/75 R 17.5 tyres. Reinforced springs on the rear axle and the reinforced front axle emphasised its ability to cope with high stresses. As a unique all-wheel-drive large-capacity van, the Vario had genuinely earned a firm place among vans designed for tough work.
In 2011, the Vario 4x4 is powered by Euro 5 compliant engines, like its 2-wheel-drive counterpart. The output levels remain unchanged.
Vito 4x4: compact van with off-road vehicle traction
A recent offshoot of the Mercedes-Benz family of vans with all-wheel drive was the Vito 4x4, introduced for the first time in autumn 2005, two years after the introduction of the current model series. It combined the handy dimensions, the excellent handling and the manoeuvrability of a compact van with the traction of an off-road vehicle. The Vito 4x4 was available in virtually all the same length and body variants as the original vehicle, i.e. there was a choice between two wheelbases and three overall lengths, and between cargo van, crew bus, and Mixto.
Like the Mercedes-Benz large-capacity Viano 4MATIC, the Vito 4x4 had permanent all-wheel drive which, in normal driving conditions on firm surfaces, distributed the power between front and rear axles in the ratio of 35:65. The developers flange-mounted the transfer box directly onto the main transmission. The front axle drive was kept very compact; it was lubricated for life and was therefore as maintenance-free as the additional front axle drive shafts.
4ETS replaces differential locks
Instead of mechanical differential locks, the all-wheel drive operated using the 4ETS Electronic Traction System, which had already proved its excellent worth in numerous Mercedes-Benz vehicles. Should one or more wheels lose traction on a slippery surface, the 4ETS automatically and individually applied braking pressure in short bursts to the spinning wheels, thus increasing the torque by an equal amount to those wheels with good traction. 4ETS used the ABS wheel sensors to achieve this. This automatic braking intervention by the 4ETS was able to simulate the effect of up to three differential locks. 4ETS was integrated into the ESP® Electronic Stability Program, whose control characteristics were specially adapted to the all-wheel drive.
Although the Vito 4x4 was not a fully-fledged off-road vehicle, it by no means shrank from off-road work. For example, the all-wheel-drive Vito’s angle of approach was 20 degrees (36.4%) (conventional drive: 18 degrees or 24.93%) and the angle of departure of the short wheelbase and short overhang variant was 28 degrees/53.17% (22 degrees/40.40%). The short wheelbase Vito 4x4 had a ramp angle of 19 (34.43%) rather than 14 degrees (24.93%). Its front axle ground clearance was around 150 millimetres and 210 millimetres at the rear. Depending on the vehicle version, its hill-climbing ability was some 20 per cent greater than for the conventionally powered Vito.
Less additional weight, practical overall height
The extra weight of the all-wheel drive was limited to just 80, meaning that Mercedes-Benz could still offer the Vito 4x4 with a permissible gross vehicle weight of 3.052 tonnes. Since, including the all-wheel drive, the overall height only increased by 7 centimetres, depending on the model, the Vito 4x4 still came in below the important overall height restriction of 2 metres. Consequently, it would fit into standard garages, multi-storey car parks and automatic car washes – an essential factor for unrestricted flexibility and everyday practical use.
Since late 2010, Mercedes-Benz has supplied the Vito 4x4 with two engine variants – Vito 113 CDI (100 kW/136 hp) and Vito 116 CDI (120 kW/163 hp) – each in conjunction with particulate filter and automatic transmission. It has proven its worth with its powerful torque and appropriately strong tractive power over even the roughest ground. Its high towing capacity of 2500 kilograms was a measure of its strong performance.
Of a technical design identical to the Vito 4x4 was the large capacity Viano 4MATIC. Engine, transmission and also the all-wheel-drive system were identical. However, the fine difference with the robust Vito was that the elegant Viano primarily targeted businesses, families or camper-van holiday-makers, whose requirements concerning comfort and vehicle exterior look were catered for by the Viano with its extroverted design and diverse lines, ranging from the lively Viano Fun, the dignified Viano Trend and the refined Viano Ambiente, to the sporty Viano Avantgarde. Camper van holiday-makers had the Viano Marco Polo, just as practical in everyday operation as well-equipped for holidays. The standard BlueEFFICIENCY package lowered fuel consumption and consequently CO2 emissions considerably (for the Vito an extra-cost option, standard for the Vito crewbus).
Compact van: Mercedes-Benz Sprinter with all-wheel drive.
Sprinter with all-wheel drive, driving shot, side view, in offroad terrain