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Talk about the different aspects of your tow car and tow advice.

4x4 v.s. diff lock

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06 Feb 2018 @ 14:58:58 pm
Des
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Hi,
Please assist.
We regularly reverse 1.5T tons down a ±30degree incline on a gravel road with a 4x4 SuV and it holds the trailer without sliding down.
Question: Will a LDV with diff lock hold it?
Thanks
Des
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06 Feb 2018 @ 16:41:23 pm
Kanneman
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You do not say if your SUV is a true 4x4 (low range) eg a Fortuner, is an "all wheel drive" / "four motion" SUV like a Subaru or VW Tiguan and if it has a manual or an automatic gearbox and if it is a diesel. All these may change one's approach.

Going down a steep hill is not a 4x4 speciality. Even a normal sedan can go down a similar hill providing the surface is sound. One needs lower gear ratios to climb, but brakes to descend. Ask any true 4x4 driver with an automatic gearbox. Automatic gearboxes do not utilise engine compression for braking in the same way manual gearboxes do.

Don't confuse one's personality with one's attitude. One's personality is who you are. One's attitude depends on who the other person is. Therefore, be who you are and say how you feel, because those who mind don't matter, and those who matter don't mind.
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06 Feb 2018 @ 19:35:41 pm
neef Herman
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Des, you say that you " reverse a 1,5 ton trailer down a 30 deg slope"
That sounds like a pretty hairy situation. For starters the run-in brakes of the trailer will be useless.
I beleive your foot will be on the brake pedal, clutch out, and in reverse.
ABS will be a negative, as it will prevent wheels from locking, and a run-away situation could happen.
The only assistance could be hill decent controll that actually locks wheels that have no traction at a given moment.
Diff lock gives traction going foreward under power, does not have any effect under braking, but saying this, if you don't need to apply brakes, it should keep the wheels turning at the same speed.
Difficult to give a good answer. Can you give the make and model of your current SUV, could explain some questions.
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06 Feb 2018 @ 19:37:38 pm
Hurricane
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You do not say if your SUV is a true 4x4 (low range) eg a Fortuner, is an "all wheel drive" / "four motion" SUV like a Subaru or VW Tiguan and if it has a manual or an automatic gearbox and if it is a diesel. All these may change one's approach.

Going down a steep hill is not a 4x4 speciality. Even a normal sedan can go down a similar hill providing the surface is sound. One needs lower gear ratios to climb, but brakes to descend. Ask any true 4x4 driver with an automatic gearbox. Automatic gearboxes do not utilise engine compression for braking in the same way manual gearboxes do.


Most of the newer SUV's and even 4x4 bakkies like the Ranger have difflock and hill descent control making the auto box argument a non-event. your statement on surface quality is also valid.

Des, why don't you borrow the LDV you are interested in and try it out?
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06 Feb 2018 @ 20:50:12 pm
HM
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I think there will be no difference, as the speed reversing a trailer down will be so slow that the only traction will be from the brakes.

Going back up I would opt for the 4X4.

The Happy Campers.
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06 Feb 2018 @ 21:19:20 pm
Kanneman
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Hurricane, you say "Most of the newer SUV's and even 4x4 bakkies like the Ranger have difflock and hill descent control making the auto box argument a non-event." What is your guess, what percentage of of 4x4 bakkies on our roads have automatic gearboxes and hill descent?

My understanding of hill descent is that the brakes controls the speed with which you descent automatically. I can recall when the Land Rover Discoveries first came out with traction control they did not have any diff locks, and the motoring writers expressed their concern about the life expectancy of the brake pads.

HM, my experience is that a vehicle's braking ability when going backwards is far less than when going forward. I think it has to do with the design of the system, expecting perhaps as much as 80% of braking to be handled by the front brakes. In reversing down a steep gradient this could very well result in the front brakes locking, whilst the less competent rear brakes are left to control the descending speed.

Unfortunately Des's question gives too little information to give a meaningful answer. Perhaps once he has given us the specifications of the vehicle involved one may consider an appropriate response.

Don't confuse one's personality with one's attitude. One's personality is who you are. One's attitude depends on who the other person is. Therefore, be who you are and say how you feel, because those who mind don't matter, and those who matter don't mind.
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06 Feb 2018 @ 21:48:55 pm
HM
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Kanneman, I think we are in agreement that the only traction will be from the brakes while reversing a 1.5 ton trailer downhill, irrespective if it is 4X4 or diff lock. Engine compression etc will not come into play at that speed. 

In my opinion the only other factor to be considered is the weight difference and tyres of the vehicles.

The Happy Campers.
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06 Feb 2018 @ 21:56:44 pm
Kanneman
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HM, if it is a diesel bakkie and it is in low range in reverse the engine compression will aid those rear brakes tremendously in controlling the pace.

Don't confuse one's personality with one's attitude. One's personality is who you are. One's attitude depends on who the other person is. Therefore, be who you are and say how you feel, because those who mind don't matter, and those who matter don't mind.
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06 Feb 2018 @ 22:45:58 pm
HM
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The only time the engine compression in low range will assist is when the brakes fail. Dan moet jy jou reverse met 'n 1.5 ton sleepwa ken boeta.laughing

The Happy Campers.
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07 Feb 2018 @ 06:27:26 am
LoneRunner
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Hi Des, ek dink bly maar by vierwiel trek.. daai bakkie met die diff lock kan dit seker maar hanteer in perfekte kondiesies, maar 'n diff lock vernaam op nat kleigrond of vir enige gladde oppervlak is maar redelik useless en bleddie gevaarlik.
Ook die SUV het beter gewigsverspreiding oor die algemeen as 'n bakkie
More sal self vertel....
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07 Feb 2018 @ 06:45:36 am
Chuck Norris
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Welkom op die forum.
As jy wil he jou drome moet waar word, moet jy eers wakker word.

Die jonge Fransmannetjie. (Parys - Frankryk)
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07 Feb 2018 @ 11:08:26 am
Des
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Gentlemen, THANK YOU for your input, much appreciated and we will definitely use this forum again.
Guided by you, our conversation moved from diff lock vs. 4x4 to tyres, vehicle weight, diesel vs. petrol, engine compression, purchase value vs. trade in value etc., and the fact that this is not a daily activity.
The end result is we are buying a Toyota Hilux 2.8 Diesel 4x4 with 65/17” tyres. The rest will be done on skill and prayer as always.
Thank you once again and have a fantastic 2018.
Des
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