articulating Unimog 435

Unimog 435


For many, the 435 (sales designation U1300/U1700) is the ultimate Unimog. It has phenomenal off-road abilities and is one of the most capable and comfortable Unimog models available. Its tremendous ground clearance, extremely flexible suspension, and superior drivetrain allow the 435 to easily transverse terrain that other vehicles would not even be able to approach. The 435 is a vehicle that can be used in the most demanding circumstances, from harsh frozen terrain in the arctic to the scorching hot sands of the Sahara. The 435 also has the ability to carry heavy equipment, supplies or implements without sacrificing its’ off-road ability. Whereas previous Unimog models were relatively slow and basic, the 435 has a comfortable, ergonomic, and functional cab and is equally as capable on-road as off-road.


The 435 Unimogs are part of the SBU range. Like other Unimog ranges, there are many variations within the SBU range such as the 424, 425, 427, 436, 437. All of these vehicles are very similar and differ primarily on engine specifications and wheelbase. Like other SBU Unimogs, the U1300 and U1700 are characterized by their boxy cabs that are larger and much more modern then previous types of Unimogs.


The 435 models were introduced in 1976 and built until 1988 when they were replaced by the very similar 437 which are still being produced. The 435 represented a dramatic change for Unimog in terms of comfort and capability. The 435 has a comfortable, if somewhat basic, cab that provides excellent ergonomics, heating and ventilation, and insulation from sound and the elements. For the first time, the Unimog had a level of comfort and ergonomics comparable to other commercial on-road vehicles of its day. As a matter of fact, the 435 cab is similar to that of the 1980’s VW Vanagon in that they both use similar interior materials and layout, and have a comparable level of creature comforts and noise levels. By modern standards, this may be a bit basic but it is very functional. The standard cab is an enclosed two door although four door DoKas were also produced in small numbers. A soft top was not offered except for in a few special military applications. Options such as air conditioning, air suspended seats, additional soundproofing and auxiliary heat were also available. While making major improvements in comfort and on-road capability, the 435 did not sacrifice off-road capability. It maintained the Unimog off-road design principles and took them to an even higher standard.

The major difference between the U1300L and the U1700L is that the U1700L has the turbocharged 170 hp engine and has heavier duty axles. Otherwise these vehicles are essentially the same. The 435 uses the same 352 engine as the 406/416 but in a higher state of tune. The U1300L has a normally aspirated 130hp OM352 while the U1700L has a 170hp turbo charged OM352A.


The U1300L and U1700L have 128-inch wheelbase. The U1300L also came in a long wheelbase version called the U1300L/37 and this had a 3700 mm wheelbase. The U1700L also came in a long wheelbase version, the U1700L/38 with a 3850 mm wheelbase.

Unimog U1300LThe 435s have an eight-speed forward and eight speed reverse gearbox. This is not a 2 x 4 shift setup as with the 406/416, but a straight 8-speed gearbox. There are two auxiliary gearboxes available, which allow for high, low and super low. High is 1:1, low is 5.76:1 and super low is 55.87:1 giving crawl ratios lower than 4500:1! As with the 406/416, torque converters and double clutch PTOs are available. In addition, the gearbox can be mated to a hydraulic motor for hydrostatic drive that provides for extreme control. Finally, there is an overdrive available for the 435 that makes it a much more relaxed than previous Unimogs when cruising at or above 50+mph.


The 435 have power steering and air assisted power brakes with disks on all four wheels. In addition the rear brakes are proportioned to load. The standard final drive ratio is 6.5:1. High-speed axles provide a 5.3:1 ratio. With the standard tires and axles ratios, the top speed of a 435 is aprrox. 52 mph. With the high-speed axle ratio and 14.5R20 tires the top speed is approx. 65+ mph. The overdrive allows for a top speed of 70+mph but is really best suited to lower the RPMs while cruising at 60+/- mph.


Unimog U1300L with RoverThe Unimog 435 is an impressive vehicle and larger than previous Unimogs. At first it can be quite intimidating because of its large proportions. It’s size is deceiving and it is much more nimble than it appears. It has an extremely tight turning radius, and with the power steering and slow crawling capabilities, it can maneuver in very confined places. A U1300 even fits in most urban parking spaces! However, the 435 is often a bit too big for most recreational off-roading although other than it’s height, it is much more nimble than a Hummer H1. It’s size and capabilities make the 435 ideal for emergency work, backcountry industries and for major expeditions to remote areas. In these roles, the 435 is truly in a league of its own. With a four ton payload rating and its off-road capability, the Unimog can get supplies, equipment or water to remote emergency locations more quickly, economically and safely than by virtually any other means. That is one reason why so many emergency crews throughout the world, from Germany to the USA, and from China to South Africa, use the 435. Virtually every government in the world uses Unimogs either through their armed services, municipalities or emergency crews. For example, in the United States, Unimogs are used in the Armed Forces, by federal agencies, state agencies and municipalities.


Like other Unimogs, the 435 is designed primarily as a tractor and implement carrier. As a result, the 435 takes a number of front and rear PTO options including 540-rpm double clutch units. In many applications PTO horsepower is limited only by engine output, which means the 435 can have up to 170HP at the shaft which puts it in the league of dedicated heavy-duty machinery and allows for serious implements such as large snow blowers. In addition, many 435 Unimogs take standard 3 pt hitch front and/or rear with a PTO driven shaft. In addition, the 435 can be fitted with single or dual circuit, multi-cell, hydraulic systems with 25+ gpm pumps. As a result, the 435 can accept an extremely wide range of implements, from backhoes, front loaders and cranes; to snow blowers, tillers, and brush cutters.


Expedition UnimogOf course, the 435 also makes an incredible expedition vehicle. It is considered one of the best platforms from which to build a high-mobility, long-range and self-contained expedition vehicle. The unique chassis and rear platform design mean that the bed and rear load space are free of any twisting or torsional stress which keeps a rear body from being torn apart in extreme conditions. An incredible amount of space is available for rear bodies or custom modifications due to the 435’s efficient cab forward design. The high payload capacity means a lot of water, fuel and supplies can be brought along without stressing the vehicle or reducing its capabilities. For example, a Land Rover 130 and a standard 435 have the same wheelbase, yet the 435 has more than twice the payload capacity and twice the space of a 130. Furthermore, the 435 has a much tighter turning radius, much better approach and departure angles and almost twice the ground clearance. The Unimog is also much stronger than the 130 in virtually every respect. It’s no wonder that most of the world’s most capable expedition vehicles are based on the Unimog 435.


The SBU Unimog is a great vehicle and in many ways represents the ultimate Unimog. They are comfortable, capable and very versatile. Most owners have found that there is no need to make any serious modifications. However for specialized applications there are a number of improvements and upgrades that can easily be applied.


Unimog 435 Options and Upgrades:

Engines:

Most U1300 and U1700 Unimogs come with the Mercedes OM352 engine. This is an excellent and extremely reliable engine that is used in Mercedes trucks and in marine and industrial applications. U1300 Unimogs normally come with the naturally aspirated130hp engine. Although 130hp doesn’t sound like much, these engines have a tremendous amount of low-end torque and move a U1300 along quite well. However, a 170hp turbocharged OM352A is a direct replacement and bolts right in. The original engine can be turbocharged, however there were modifications made to the turbo version engine, such as extra oil passages and extra cooling, to allow it to handle the extra heat and stress caused by the turbo. While many have successfully installed a turbo on the original engine, the best method is to use an OM352A engine that was originally intended for a turbo.


In addition to the OM352 and OM352A, the OM 366 and OM366A are also used in SBU Unimogs and can easily be installed in a U1300 or U1700. These are direct replacement engines and can be installed using genuine Mercedes parts. The OM366 engine has between 130 and 214 horsepower, depending how it is configured. In addition to more power, it is a more modern, cleaner burning engine that is also somewhat more fuel-efficient. Like the OM352, the OM366 is an extremely durable and reliable engine.


Of course either the OM352 or the OM366 can be custom tuned to bring out more than stock horsepower. The OM352A can be tuned to between 200-225 HP whereas the OM366A can be tuned up to about 250-275 HP. However these are not Mercedes approved modifications and may affect the longevity of the engine.

Special Drive Train configurations:

PTO units:

540 rpm front pto
H igh Speed Variable rpm front PTO
540 front rear PTO
540 front rear PTO double clutch driven
540/1000 RPM shiftable PTO double clutch driven


Overdrive:

2-speed gear-splitter that works in all gears forward and reverse. The gear-splitter increases any gearbox ratio by 22% when engaged.


Underdrive Gearboxes:

There are several auxiliary under drive gearboxes available. These gearboxes are installed as auxiliary gearboxes to the stock gearbox and can be engaged in all gears forward and reverse.

-3.19:1 for a crawl ratio of approx. 271:1
-5.76:1 for a crawl ratio of approx 490:1
-55.87:1 for a crawl ratio of approx. 4750:1!
*The 55.87 gearboxes must be added onto the 3.19 or 5.76 gearbox.


High Speed Axles:

The standard axle ratio for the U1300 is 6.5:1 and for the U1700 it is 6.4:1. With the optional high speed ring and pinion the ratio for the U1300 is 5.3:1 and 5.4:1 for the U1700. This translates to approximately a 19% increase in the overall ratio.

Tires:

The stock tire size is 12.50x20. However 14.50x20 fit without modification. Other sizes such as 11.00x20, 12.00x20, 13.00R20, 12.00R22.5, 14.5R24 are options and even extreme high flotation tires such as 22-20 tires are possible.


Comfort:

The stock cab, even with the standard army seats, is quite comfortable and the ergonomics are excellent. The power steering, power brakes and soft coil suspension means the 435 is comfortable and easy to drive. However, by modern standards, the cab is a bit basic and somewhat noisy. There is no need to shout or speak particularly loud but extra sound insulation can bring the noise levels down to a point that the cab is actually quiet. Orthopedic air seats, radios, heated windshield, extra heaters, carpeting, etc can all be added to make the cab even more comfortable.

 

Click Here for a detailed list of 435 specifications and weights