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OKA NT Truck Description 2006 - 2014

The Truck Manufacturer: OKA, Bibra Lake, Australia.

In August 2006 the first OKA NT left the factory in Bibra Lake near Perth in Western Australia. It is ours!
If all goes well, the OKA will tour Australia for the next 3 years and then be taken around the world.

2011: Unfortunately, after producing around 20 truck of the new type OKA closes its doors in 2011. There is a lot of speculation around the real cause of the closure. For us it means that we lose our main parts supplier. Since the truck is mainly built from industry standard parts this is not a drama yet. The problem is only to find out what parts OKA used for the truck and where they can be ordered from.

The "OKA owners club" is still very active and we hope its members will be able to help us should the need arise.

Below is a description of the truck, for the description of the camper back-section click here.

Refer to the OKA Specifications page for further, more technical, details.

The Truck

This is the previous model, the OKA LT.

The left picture shows the new model, the OKA NT after its "maiden" run, but still with a few parts missing. The right picture shows the final result with the back-section mounted.
The cabin is a welded steel frame covered by steel plates and is roll over protected.

It still looks the same from the outside as the previous model, but that's where most of the similarity ends.
The OKA NT is in many respects stronger and better as its predecessor. Track width, wheelbase and overall length are all slightly larger.

OKA uses a lot of "standard" automotive components to build their trucks which should make it (hopefully) relatively easy to get most of the spare-parts in the future, including outside of Australia.

These trucks are mainly used for military and mining purposes as well as by the Australian tour-operators for their trips into the rough outback. This truck is perfectly suited to be used as a camper due to its size, payload and ruggedness.

Our OKA NT cab-chassis is driven by a Cummins 4-cylinder, 4-litre turbo charged and inter-cooled diesel engine.
It delivers 170 HP and has an enormous torque of 600 Nm. Highway-speed is up to 120 kmh.

Due to price reasons we chose the 5-speed, cable shifted manual transmission gearbox.
4WD is engaged by a BAE / Vickers semi-permanent (also cable shifted) transfer case.

The vehicle has cloth seat covers and tinted windows and is registered to carry one driver and one passenger.

The trucks standard GVM is 6500 kg.
Additional air-springs are fitted by an aftermarket company to increase the GVM to 7260 kg to comply with legal requirements.

2010: The installed solution is technically flawed and mechanically of very bad quality. The whole airbag mounts have to be replaced.

2012: The whole suspension isn't sturdy enough for our wait and has too much play all over. We change the whole suspension with all its parts (spring package, shackles, shackle pins, bushes). All is done by the renowned Swiss company "Bieri Federn- u. Bremsservice AG" in Kriens, Luzern, Switzerland. The result is impressive. The OKA drives "like on rails". Below some details of the renovation.

Front suspension: The new spring packages are thicker (all 10 mm leaves) and nicely staggered. To avoid the drag link contacting the spring package a spacer is required under the steering arm. On the right-hand side, a metal plate eliminates the notorious play.

Rear suspension: The new spring package and the new sturdy shackles. Front and rear are identical.

The new 24 mm Spring pins and the new mounting hardware on chassis and shackles. They are of German quality. No play anywhere.

Fuel capacity is 115 litres in each of the 2 diesel tanks.
The photo above shows the fuel tank on the right side.

2012: The original, lockable fuel caps constantly brake. We replace them with new types. This is quite an ordeal. There are no unventilated, lockable fuel caps on the market and the non-lockable ones are also leaking. OKA needs sealed caps because its tanks have airing lines. If the cap is also ventilated the diesel leaks if the OKA is in a sloping position. After some trials and some Araldite, we are able to solve the issue. The tanks are now seriously locked - Fort Knox style.

Behind the fuel tank (left side of picture) a custom built storage box was added.
In front of the tank the main battery is covered by aluminium checker plate. OKA's main battery is normally mounted on the opposite side and is not covered.

2010: The tank capacity is increased, mainly for South America. 4 jerry cans are stored in a box on the roof rack. They are normally empty.

In front of the left fuel tank is the checker plate covered floor heating compartment and at the back, the standard OKA air step. The air step had to be relocated because of the position of the door.

2013: In South-America some tracks climb to an altitude over 5000 m above sea level.
During the night temperatures can fall below -20°C.
This is a problem for the diesel fuel because it may gel even when using fuel additives.
If this happens the motor cannot be started since the diesel clogs the fuel filter.
Also, the Diesel heater will probably get in trouble under such conditions.
To overcome that problem as good as possible we cut a hole into the heater cover and moved the exhaust of the heating above the diesel tank.
With a blanket we conserve the heat of the heating and warm the diesel in the tank.
Under such conditions the motor will be heated anyway at night.

The black round cover at the front (left side of picture) hides the various air valves for the diff-locks, air steps etc.
Below the tank is the red PTO (Power Take Off), the blue hydraulic motor and the 30-litre hydraulic oil tank.
All of it is used for the hydraulic winch.

Each fuel tank has its own sediment bowl and filter to trap water and dirt.

Above the diesel filter on the right side is the easy accessible air filter.

Dust from the air filter exits just below the filter due to the overpressure within the filter case.
Also due to the overpressure and the shape of the nozzle, no water enters the filter even if submerged.
There is a snorkel built into the cab bodywork.

The new optional bull bar is bolt-on and therefore easy to repair. The bull bar is delivered with two antenna attach points.
Bull bar and bumper are both hot dip galvanised.
Two strong recovery hooks at front are standard and are built into the chassis.
The main lights are covered by strong stainless-steel mesh for stone protection.

We added cables between the bull-bar and the back-section to protect the cab from branches while driving through bushland and forests.
Branches up to 5 cm simply bend away or break.

2010: For improved security reasons on our world tour the standard entry steps on the bull bar are now covered to prevent somebody from climbing on the rolling truck. This happened to Ruedi in his VW-camper in Italy in 1973.
Padlocks have been added to further secure the doors and the side windows are now laminated and shatter proof.

2013: In Tacna (Peru) the door on the driver side was forcefully opened.

The "locking bow" of the padlock (grade 4) was ripped off in no time with some sort of a crowbar.
We now use stronger padlocks (grade 8) from Abus (90/50 Titalium).

The standard door lock was forcibly turned open using a screwdriver.
This is easy because the door handles are made from plastic and offer no resistance.
The new door locks are reinforced with an aluminium plate to add more security.

The leaf springs have four layers under the eyelet making them much less likely to break.
There are 4 double acting, gas charged shock absorbers installed on the front axle (2 are optional).

Clearly visible is the new 8 t axle with the optional air locked differential.
Many of the vulnerable parts are protected by bash plates.

The back axle also has 4 shockies (2 optional) and has an optional air operated diff lock installed.
Front and rear axles have no stabilisers (anti sway bars) installed. The axles have an incredible articulation of 14 inches.

2011: After the many problems we had mainly with the diffs (2 axles and 8 diffs replaced on warranty) we decided to remove the diff-locks for good.
Diff-Locks put a lot of strain on the drive train and our axles are of the worst possible quality.
These two parameters simply don't match. In addition, our vehicle is very heavy and this adds even more strain to the whole system.

2010: The hubs are prepared for "Central Tyre Inflation" and have also connection for hub-breathers. Since there is a seal between hub (greased) and differential (oiled) the hubs should have breathers installed to avoid water from entering the hubs while wading through cold water. This has now been done.

Visible in the middle of the picture is the cable shifted 2 stage transfer case and the flange bolted drive shafts.

Huge ventilated disc brakes are used on both axles. They are power boosted by air over hydraulics.
Right behind the transfer case (visible as a round thick disc) is the air actuated park break.
Since it is connected to the transfer case it works on all 4 wheels if in 4WD.

2010: Due to our weight the brake power of the motor is insufficient. We decide to be the first clients to install an exhaust brake, a "PacBrake".
The result is fantastic. The exhaust brake is controlled by the electronic motor management system (ECM).
Never the less it can be manually switched on or off at any time using the brake pedal or accelerator.
At the same time, we exchanged the exhaust system with a stainless-steel version.

The 305/70 R 19.5 Michelin XDE 2+ tubeless tyres are mounted on "Titan" 19.5" x 8 1/4" bolt-together rims.
"Second-Air" bead-locks are fitted to the wheels to prevent the tyres from sliding off the rim when driven with very low pressure (mainly on sand).

2009: The bead-locks have been removed.
They constantly destroyed themselves when the tyre slightly slipped on the rim when breaking hard.
(Apparently the newest version of the bead-locks has been improved to hopefully avoid this problem.)

The front wheels are equipped with AVM free-wheeling hubs to reduce fuel consumption while driving in 2WD.
The free-wheeling hubs are protected by hub steps.
To help in difficult terrain the truck is equipped with optional air-operated diff locks front and rear.
All the above (except the tyres) are options supplied by OKA.

Normally the spare wheel is installed at the rear end of the truck, adversely affecting the departure angle.

2009: We build a new and lighter spare wheel carrier which also carried the 6 fibre glass sand boards.
The second spare tyre is still on the roof rack.

The hydraulic winch (OKA optionally supplies the Warn M15000 electrical winch) is mounted to the chassis behind the first cross member.
The synthetic rope runs through a standard fairlead which is also fixed to the chassis and not to the bumper.
The winch runs on a hydraulic motor driven by the power take off on the main gearbox.
The winch is operated from inside the cab. It has its own 30-litre oil tank and can be run constantly but only as long as the motor runs.
This is not a major concern as an electrical winch of that size with such a heavy load would also not work for long if the motor stalls or not at all if in salt water.
The chance that the motor fails at the same time as the truck is bogged is very unlikely except if caught in very deep water.
The only real disadvantage of a hydraulic winch is that actively driving and winching is not possible at the same time. But this is not recommended anyway.

For places where there are no trees available we carry a ground anchor. As recovery sessions in soft sand have shown the truck simply pulls the ground anchor underground through the sand making recovery even more challenging.

2010: In many recovery situations the ground anchor has never worked as expected. It has been removed.
In the future we will use our spare wheel instead, as many others also do.

We also carry glass-matt type sand-ladders which have already proven to be very rugged and reliable even for this heavy weight truck.

OKA's standard dashboard takes up 2/3 of the cabin's width. It contains all the standard instruments and switches and has additional pre-defined slots for a UHF CB-radio, some more instruments and switches.

The added UHF CB radio (not supplied by OKA) is at the upper left corner to be operated by the co-driver.
The radio/CD/MP3 player (OKA supplies a different type) has an attached interface to be able to use an iPod as music source when no radio stations are available in the outback.

The 2 red switches below the radio operate the PTO used for the hydraulic winch and the free spooling of the winch.

The middle console holds (from left to right):
- UHF radio microphone
- HF radio speaker (2010: removed)
- HF radio microphone (2010: removed)
- HF radio remote console (2010: removed)
- Hot-standby GPS (mainly used for biking and hiking)
- Compass (2010: removed)
- Lever for the air-operated handbrake.

The handle at the bottom of the picture right of the console operates the hydraulic winch.

The console at the left side of the truck has been custom-built for navigation and holds the main GPS, the on-board PC's touch screen monitor and the switch to start the PC.
Both screens are readable in full sunlight.

The HF transceiver and the iPod holder are installed alongside the co-driver's right leg.

2010: The co-pilot gets its own spotlight. The HF-transceiver has been sold. It had never been used and without a special permit it would be illegal to use it internationally.

2012: One known annoyance of the OKA's rear cab air-condition is that it every so often splashes water into the driver cab.
This is due to the fact that the condenser unit is mounted exactly level.
The condensing water collects at the condenser unit until the driver stops sharply.
Then the accumulated cold-water splashes onto the driver and passenger without any warning.
The unwelcome bath can be avoided by adding a splash-wall in front of the condenser unit which defers the water back into the air-condition housing and down the drain tubes.

2012: The motor bay has been insulated using a heavy carpet. This drastically reduces the mid- and hi-frequency noise in the cab (seen in Oz in Dave Hallendal's OKA).

2013: Since South-Africa we had problems using the 4WL or 4WH.
Either of the two did not engage correctly and/or fell out of gear.
If both were correctly setup the Neutral or/and the 2WH where failing.
There are 3 possible reasons for this to happen:
1. Too much play in the lever in the dash
2. Wrong adjustment at the transfer case and
3. The matrix for the lever is produced out of tolerance. On our OKA point 2 and 3 where the case.
The play was fixed in Germany but it didn't fix the problem.
We now rebuilt the matrix to the correct measurements and now it works fine (just cut the metal plate apart, turn the right side and drill/grind/file your new matrix).
Neutral and 2WD were out of tolerance by some millimetres.
Also, the angles of the "teeth" should be in line with the different lever position and not 90° to the matrix. This eliminates wear.

Behind the co-driver's seat a small shelf has been fitted.
On top are 2 red boxes containing survival and medical supplies.
Should the truck catch fire they can be removed very quickly.
Above the red boxes, two breathing masks are mounted against the back wall.
They will prevent smoke intoxication for up to 10 minutes as long as there is enough oxygen available.
This should (hopefully) be enough time to escape if caught in burning forests, heavy bush fires or in tunnel accidents.

A PC is installed under the shelf. It is a Swiss made military grade product.
It is fully shock, dust, and water resistant and can be used even on heavy corrugated roads.
The PC is operated by a dust and water resistant standard keyboard as well as a special keyboard designed for the navigation software.

The PC is used for navigation, up and downloading maps, tracks, routes and waypoints to and from both GPSs.
All data is administrated in the navigation software.

In addition, email can be sent and received via the sat-phone using special software.
This can be done even while driving on the road at any time and in about any place in the world.

Internet access is possible using the USB modem. It works with reasonable speed also in most of the smaller villages.

The generated data is regularly saved on a network disk on the (wireless) LAN hub installed in the back-section.

The sat-phone is located above the co-driver's seat and the battery is constantly being charged.
A headset also allows phone calls while on the move.

The antennas for the sat-phone and for both GPSs are located on the roof of the back-section to guarantee optimal reception.

An additional handheld UHF CB-transceiver is located beside the sat-phone. Its battery is also constantly being charged.
The transceiver can be removed and used to keep contact between the co-driver and the driver while the co-driver is outside the vehicle or is examining the track ahead.

Between the 2 seats a Swiss made Rako-Box contains all the maps, travel-guides and other items permanently used.

A 6 kg foam-type fire extinguisher, an electronic rust protection unit, the dual battery charger as well as other often used tools are all located behind the driver's seat.



No liability for timeliness, integrity and correctness of this document is accepted.
Last updated: Thursday, 10.01.2019 4:12 PM

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