This product is currently in the development stages, the information on this page will be updated as we progress.

Gearmaster
™Portal Axle
For
Nissan GQ and GU Patrol
Last Updated: 22/11/09
| These portal axles have been designed to directly replace the original Nissan GQ & GU Patrol live axle assemblies as fitted to all models from 1988 on. |
| At the present time the portal axle assemblies have
undertaken full stress testing and have an axle rating of 1530kg. The engineers report is now complete, it includes the
necessary lane change testing now required by all Australian authorities. All of the testing
was performed with 35"
tyres fitted. Yes, this means you will be able to legally drive your 4wd
on the road with 35" tyres. The Portals are currently accepted in the
following States - Victoria - NSW - SA - WA - NT - TAS. The State of QLD is pending. Our prototype axles have been in operation since July 2006 and have travelled over 80,000km. For more details click here. |
| Ground Clearance
and Track The portal transmissions have a vertical offset of 101mm/4", this 101mm lift raises not only the body and chassis it also lifts the differentials by the same amount. With the addition of 35" tyres the total increase in ground clearance is approximately 150mm/6" over standard. When 35" tyres are fitted, the differential to ground clearance is equivalent to having a standard live axle fitted with 43" tyres. The portal transmissions increase the axle width by 100mm per side. A combination of 25mm or 50mm positive offset rims fitted with 35" tyres are used to correct the steering geometry. These rim combinations give an overall 150mm or 100mm increase in the vehicles overall track. Vehicles fitted with these rim offsets have undertaken and easily passed lane change tests conducted at Sandown race track. |
| Reduced Bump Steer
compared to suspension lifts A suspension lift is not required, which keeps the control arms, and pan hard rods flat. However a change to heavier springs may be required if your vehicle is to be fitted out with the usual long list of off road accessories such as long range fuel tanks, water tank, drawer system, dual batteries, winch and the usual front and rear bar work etc. Some advantages of minimal suspension modifications are, better handling due to no increase in bump steer. A softer ride can also be experienced with virtually flat control arms. Better tracking due to, unchanged caster angle. Improved articulation is also experienced due to the increase in the vehicle track. Less body sway is also experienced due to the standard height springs and retention of the sway bars. NOTE: If required sway bar disconnects can be fitted. |
| Drive line
vibration Drive line vibrations are a common experience when hi lift suspensions are fitted. With minimal or no suspension lift along with reduced drive line angles no drive shaft vibrations are experienced. This is due to the universal joints operating within their designed operating range. |
| Increased drive line
strength The torque load which is normally exerted on the differential, axles and constant velocity joints is transferred into the portal transmissions, the amount of load transferred is proportional to the gear ratio used in the transmission. The gear reduction of 1.4:1, offers a load reduction of 40%. The 40% gear reduction offers this same percentage increase in strength to all of the transmission components from the CV joints back to the engine. Conversely, the 1.22:1 ratio reduces the driveline torque load by 22%. |
|
Improved braking All portal assemblies are supplied with a new smaller bore brake master cylinder for increased line pressure. ADR approved braided brake hoses are also supplied. New disc rotors are fitted and the brake callipers are reconditioned and fitted with new disc pads. |
| Lubrication Oil is used for lubrication and is easily checked using the filler/level plug fitted on the differential side of each portal transmission. A drain plug is also fitted on the same side for ease of servicing. Each transmission holds approximately 400ml of oil. The oil supplied with the portal assemblies is high quality synthetic. |
| Breather System The portal Transmissions are equipped with external breather ports to allow hoses to be fitted. The portal axle assemblies are supplied with breather hoses, manifold, and filters. Tyre Size and Off set rimsThe portal Transmissions are supplied with a set of five 17"x8" steel rims with a 25mm positive offset. For correct steering geometry these rims must be fitted with 35" tyres. 17"x8" alloy rims with a +50mm positive offset can be used, the alloys will cost extra. 16"x8" rims with the correct positive offset will only be available with the GVM upgrade. Front Tyre Clearance (Control Arm Spacers)When fitting 35" tyres to Nissan Patrols it is necessary to move the front axle forward, this is to help the tyre clear the rear of the front guard when turning. Marks 4WD Adaptors manufacture and supply the required spacers with the portal axles. For more information click here. Rubber FlaresAs there is an increase in the vehicles track of over 100mm the tyres will protrude past the mud guards, to overcome this problem the portal axles are supplied with the necessary rubber flare and fixing screw kit. For more details click here. GQ Patrol Portal Axles To fit portal axles to Nissan GQ Patrols the rear axle housing must be widened to make it the same length as the GU Patrol. We now manufacture the necessary components to make this possible. The front axle assembly must be replaced by one from a GU Patrol. Some of the advantages of upgrading are: wider track, larger brakes, stronger king pin/swivel housing as the bearings are further apart and the housing is much stronger. The other advantage is much larger/stronger CV joints. Diff Centres The rear diffs in GQ and GU Patrols come as either the smaller H233B with 33T spline axles or the large H260 diff with 37T spline axles. Either of these diffs can be built into a portal axle. Please NOTE: Fewer diff ratio options are available for the larger H260 Diff. Steering Track Rod All Nissan front portal axle assemblies are supplied with a new heavy duty track rod and new ball joints. Free Wheel Hubs The front portal axle assemblies are fitted with AVM free wheel hubs. The hubs are not the standard Nissan type, the output axle shaft from the portal is much larger than the original Nissan. To accommodate the larger shaft we have manufactured a new centre spline section for the hub. If the vehicle is to be used solely for off road events such as rock crawling the free wheel hubs can be replaced with rigid driving flanges which are used on the rear portal axle. Fully Floating Rear End All rear portal axle assemblies are full floating which means the rear axle no longer supports the wheel directly. All four wheels are supported using standard Nissan front, wheel hubs. The hubs are supported on a stub axle which is made from 4140 alloy steel, all four stub axles are the same. The inner wheel bearing is a standard Nissan type while the outer bearing is one commonly found in a Toyota. The Toyota outer wheel bearing was selected because of its larger bore size which allowed us to fit the larger output axle. Portal Gear RatiosTwo portal transmission ratios are now available: 1.4:1 and 1.22:1 The 1.22:1 ratio is now available and makes the overall gear reduction 7% lower than standard when you allow for the 15% increase when fitting 35" tyres. This reduction helps to keep the overall conversion cost down as diff ratio changes are not required to achieve normal road speed. |
For optimum on road performance it is necessary to maintain the original engine RPM/road speed ratio. In a vehicle fitted with 1.4:1 portal axles and a manual transmission we recommend using 3.54:1 diff ratios with one of our new overdrive 5th gear sets, this combination with 35" tyres will only increase the engine speed by 50RPM at 100 kph. This diff ratio perfectly suits a vehicle fitted with an automatic transmission. The two combinations above are the only ones suitable for on road use when using the 1.4:1 portal ratio.
For more information on the 5th gear option click here.
If you intend building a competition vehicle click here for alternative ratios.
Speedometer RecalibrationAfter the portal axles have been fitted the speedometer will require recalibration to allow for the change in axle gear ratio. The GQ-GU portal axle kit is supplied with with one of our electronic tyre match boxes. Click here for more information.
The Axle Build
The road registered portal axles are solely built by Marks 4WD Adaptors using your original standard axles.
The front axle assembly is completely stripped and all of the parts are thoroughly cleaned. The diff centre is stripped and cleaned, we then fit new bearings, change the ring and pinion ratio if required and a ARB air locker is fitted if requested at the time of ordering. The axle housing (banjo housing) is checked for straightness using our purpose built laser aligning tool, the housing is then straightened if required. The housing is then sealed and sand blasted clean. We then fit the swivel housings using new king pin bearings and a re-machined lower king pin. An additional king pin bearing in the form of a ball joint is fitted under the lower king pin. A strut is fitted to the ball joint and is then attached to the main housing (banjo housing) via two brackets welded to the housing. An additional brace made from chrome molly is then welded to the long side of the banjo housing. The banjo housing is again checked for straightness using our laser aligning tool, the housing is then straightened if required. When all is well the banjo housing, swivel housings, struts, hubs and portal housings are all painted prior to assembly. All of the bolts, washers, nuts including the seal retaining brackets are freshly zinc plated.
The front portal is then assembled using all new CV joints, axles, gears, shafts, bearings and seals. The brake rotors are replaced and new bearings fitted to the hubs. The new AVM free wheeling hubs are fitted with the new splined centres before fitting to the wheel hubs. The brake callipers are striped and cleaned, new seals are fitted with new pistons if required. The callipers are then fitted to the portal housings along with new brake pads. New braided brake lines are fitted between the callipers and the diff brake pipes, a new braided brake line and t-piece is then fitted to the diff housing ready to fit to the chassis in your vehicle.
The rear axle assembly is completely stripped and all of the parts are thoroughly cleaned. The diff centre is stripped and cleaned, we then fit new bearings, change the ring and pinion ratio if required and a ARB air locker is fitted if requested at the time of ordering. The axle housing (banjo housing) is checked for straightness using our purpose built laser aligning tool, the housing is then straightened if required. The housing is then sealed and sand blasted clean. The portal gear housings are then fitted to the banjo housing using high tensile 4140 steel studs and nuts. The additional torque bracing can then be welded to the banjo housing. The additional chrome molly bracing is then welded to the banjo housing. The banjo housing is again checked for straightness using our laser aligning tool, the housing is then straightened if required. When all is well the banjo housing, hubs and portal gear housings are all painted prior to assembly. All of the bolts, washers, nuts are freshly zinc plated.
The rear portal is then assembled with all new bearings and seals. As with the front portal the brake callipers are striped and cleaned, new seals are fitted with new pistons if required. The callipers are then fitted to the portal housings along with new brake pads. New braided brake lines are fitted between the callipers and the diff brake pipes, a new braided brake line and t-piece is then fitted to the diff housing ready to fit to the chassis in your vehicle.
NOTE: In this kit we supply a GU front end and a GQ rear end which has been widened to the same track as the GU. They are sold on an exchange basis for your original GQ axles.
Fitting cost for the above is $1500 inc GST This includes labour to remove and refit the front and rear diff assemblies, fit new springs and shockers if required, fit the new brake master cylinder, braided brake lines and bleed the brakes, fit the portal breather system, supply oil for the diffs, fit the front control arm spacer kit, fit the rubber flare kit, fit the tyre match box and calibrate the speedometer,
Engineers Report $795 inc GST
Ratio changes from your original diff ratio will incur the additional cost of the ring and pinions.
NOTE 1: An additional $220 inc GST will be charged for fitting each ARB Air Locker.
NOTE 2: An additional $165 inc GST will be charged for fitting each new Ring and Pinion.
Optional Diff Ratios
Click here for ratio options
Optional 35" Spare Wheel Carrier for GU Patrols
Click here for more information
Copyright © 2006
Marks 4WD Adaptors
Last modified:
June 01, 2010