OziExplorer replied:

800kg is chicken feed for a Patrol. Don't labour/lug the engine is the prime requirement. I tow a 1,470kg trailer in 5th gear in the 2.8L diesel Triton and wack the cruise control on.

ken d replied:

Ray

Each situation is different, obviously a light but large trailer is hard to pull in the wind, a heavy trailer hard on the hills.
Generally I say is whichever gear requires less throttle.
If you find you're in 5th with your foot burried into the floor shift back to 4th.
This said there are generally no downsides to continuously running in 4th. A little extra noise but otherwise it's putting less load on the engine and box.

Ken.

Will replied:

Ray,

It really depends on the configuration but as a rule, fifth gear is not designed to haul, it is an over drive and sits on the side of the gear train and through very small (comparatively) bearings and fine teeth to keep it quiet.
A 6 cyl 2.8 Patrol would not have much trouble with fifth because it is a six cylinder and the ratios are very low ie: 3600rpm at 100kms.
The 3.0L patrol is the worst because it is a four cyl with lots of torque, which means that the torque for each stroke is greater.
You can still tow in fifth, but as soon as a hill comes up (even if you have the power to stay in fifth), change back to fourth.
Will

Member - Melissa replied:

Hi Ray,

We tow an offroad camper trailer with our 4.5L GU Patrol (manual). We don't hesitate to use 5th for highway cruising. The GU barely knows the trailer is behind it. Obviously, we knock it back to 3rd or 4th as the need arises.

:o) Melissa

Mudguard replied:

g,day Ray i drive a 2.8 GU and tow a camper trailer and when loaded for extended trips the GVM is fairly high This model has the lighter gearbox but will pull the weight no problems just match the speed for the gear and not labour it in 5th.To answer another question the 2.8 lt (6cyl) is lighter than the 3.0lt (4cyl) has a greater carrying capacity smallerturning circle and with the addition of a unichip and bigger exhaust is quite capable on and offroad. cheers.