Danish Unimog 416

Unimog 406 and 416


The Unimog 406 (sales designation U900) and the 416 (sales designation U1100) represent one of the ultimate vehicles for off-road use, be it as an implement tractor on a farm or worksite, a rock-crawler or as a remote expedition vehicle. Stock 406/416 Unimogs are more capable than most custom “built” 4x4s and the engineering standards exceed that of other 4x4’s. The 406/416 has ground clearance, low gear ratios and axle articulation on a level that few other vehicles can match. That, combined with the torquey, heavy duty 5.6 diesel, bullet proof drivetrain, large tire options, power steering and awesome approach and departure angles make the 406/416 one of the most capable off-road vehicles anywhere. The 406 and 416 are specifically designed to take a large number of PTO and hydraulic implements and one Unimog can easily be used as a front loader, backhoe, snowplow/blower, dumper, and agricultural tractor.


The 406, and its long wheelbase sibling the 416, have many variations and there are other similar versions of the 406/416, such as the 403 and 413, 417 and 419. The 406 was introduced in 1963 and the 416 followed in 1965. They were built until the late 80’s with some derivations being produced into the 90’s. The 406 has a 94 inch wheelbase while the 416 is virtually identical but has 114 inch wheelbase. The 406 and 416 use the same cab, which was produced in several variations including a two door soft top, two-door hardtop and four door DoKa. This cab is a vast improvement over the 404 but still spartan and somewhat awkward by modern standards. The 406 and 416 share the same engine, gearbox and axles.


The 406/416 are powered by the Mercedes 6 cylinder, 5.7 liter, OM 352 that generally produces between 85 to 110 hp depending which application it is in. Unlike earlier Unimog engines that were based on automotive engines, the OM352 is a low revving, heavy-duty truck engine. This engine is famous for its strength and durability and is still used throughout the world in trucks, boats and heavy-duty machinery. Generally in the 406, the engine produces 85 hp and in the 416 it produces 110hp. However it can easily be tuned to 125hp for both the 406/416 by upgrading the injector pump.


The 406/416 gearbox comes in two shift patterns. The first is a six speed forward, two speed reverse gearbox similar to the 404. The other variation is a 2 x 4 four speed with eight forward ratios and four reverse ratios. The 2x4 is virtually the same as the 6 speed except for the shift pattern. This gearbox has a four-speed shift pattern with an additional hi/low range shifter similar to other 4x4 systems although it does not use a two-speed transferbox. Both of these gearboxes can be mated to the “Cascade” auxiliary gearboxes which provide up to three reductions with crawl ratios from 100:1 to as low as 4000:1! Torque converters, double clutch units and front and rear PTOs are also possible with this gearbox depending on the configuration. All 406/416 come with HD power steering and power brakes. Early 406/416 came with four-wheel drum brakes while the later models came with four-wheel disk brakes with automatic load proportioning. As with other Unimogs the 406/416 use portal axles with reduction hubs. The standard final axle ratio is 6.5:1 although 6.0:1 and 5.3:1 are also available. With the standard gear ratios and 12.5R20 tires, the 406/416 has a top speed of about 52 mph (@2800 rpm) while with the high-speed axles and 14.5R20 tires speeds of 65+ mph (@2800) are achievable. The OM352 will cruise for extended times at 2800 rpm no problems although it is a bit loud in an uninsulated 406/416 cab.


The 406/416 make truly awesome off-road vehicles, suitable for anything from wilderness emergency vehicles to extreme expedition vehicles. They are used by armed forces and emergency crews world wide for their ability to safely, quickly and comfortably access areas that most vehicles are unable to even get close to. They are also popular as expedition vehicles because in addition to providing more capability and freedom than other popular expedition vehicles, they also provide more space and cargo capability which provides a higher level of freedom and comfort. Finally, because of their awesome ground clearance, articulation, and low gearing, Unimogs are respected by extreme off-roaders and rock crawlers. It is not uncommon for a Unimog to spend its first decade as an emergency vehicle or tractor, followed by a decade of driving through Africa, the Sahara and Asia as an expedition vehicle and then to be used as a trials off-road truck. The Unimog is equally at home in any of these roles.


Of course, 406/416 are designed to be used as a tractor and/or implement carriers and at this they excel. Both the 406 and 416 make excellent medium duty tractors and usually come equipped with PTO’s and hydraulics; including 540 rpm, high speed, double clutch PTO’s and five circuit hydraulics with heavy duty pumps. The PTO’s use standard shafts and standard three point hitch units and can be mounted front and rear. As a result, these Unimogs can take everything from backhoes and frontloaders, to brushhogs and mowers, to snow blowers and plows. Other useful features such as 3-way dump beds, and air compressors with air brakes for trailers are available. A 406/416 will take as many implements as most John Deere or Kubota utility tractors, but do it better and for less money. Furthermore, you can drive to the worksite with a Unimog which adds even more to its versatility.
In their standard form, 406 and 416 are awesome off-road vehicles. However, driving a typical standard 406/416 can come as a shock to somebody who hasn’t driven a Unimog. They will certainly seem slow, loud and somewhat crude. This takes a little getting used to but few find it a problem once they get accustomed to it. Nonetheless, it is pretty simple to make the 406/416 much more comfortable and practical for road use. This has largely to do with adding more insulation to the cab and engine cover, installing high speed axle ratios, installing larger tires and upgrading the injector pump. These modifications transform the 406/416 into a whole other league, dramatically improving the on-road characteristics while at the same time actually increasing off road ability.


Unimog 406/416 Options and Upgrades:

Engines:

The OM352 can easily be tuned to 125hp using Mercedes approved specifications in both the 406 and 416. The OM352 can also be custom tuned up to 150hp. It is also possible to turbo charge the OM352. However, unlike the 435, a turbo is not a direct swap and involves modification to the cab. The turbo is a very tight fit and intrudes into the cab. As a result this is not a straightforward or practical modification but with some ingenuity it is certainly possible.


Special Drive Train configurations
:

There are no overdrives or gear-splitters available for the 406 and 416. However, for those who want to increase the top speed, there are two options; "fast axles" and/or larger tires. "Fast axles” involve installing lower ratio ring and pinion gears. This will provide approx 20% increase in top speed. “Fast axles” are not recommended for the 406. The short wheelbase, combined with the large tires and high center of gravity, make the handling on a 406 unpredictable and potentially unstable at higher speeds, especially if there is poor traction.


As with other Unimogs, increasing the tire size gives a higher top speed, better cruising rpm and more ground clearance. 14.50x20 tires fit with little or no modifications.

PTO units include:

540-rpm front PTO
High-speed variable rpm front PTO
540 front rear PTO
540 front rear PTO double clutch driven
540/1000 RPM shiftable PTO double clutch driven

Underdrive Gearboxes:

The 406/416 were available with the “cascade gearbox” which essentially adds three additional ratios ranges giving the vehicle High, Intermediate, Low and Super Low. Just like Hi/Low on normal 4x4s, all gears on the gearbox are available in each range giving a total of 24 gears on the six speed. The ratios are a follows:

High 1:1
Intermediate 1.27:1
Low 4.67:1
Super Low 42.9:1
 

Comfort:

Unimog 406/416 cabs tend to be pretty loud seeing as the occupants are virtually sitting next the big 5.6 liter diesel engine. However, Mercedes did little to sound proof the cab so there is room for lots of improvement. Insulation, sound deadening mats and carpeting can bring the noise levels down quite a bit and add to overall comfort. Of course the 406/416 will never be a quiet vehicle by modern standards no matter how much soundproofing is used but it can be certainly made tolerable.


Click Here for a detailed list of 406/416 specifications and weights