Rod Mac wrote:

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My thoughts.

Rule one, never use cruise control in wet weather, towing or not, why ? in the event of slippage due to aqua planning the cruise control can sense a slower than the set speed and will try to accelerate back to the set speed, if you are not quick enough to cancel the cruise control you could be in a whole lot of trouble.

regards.Rod Mac

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 Absolutely true! My "play" car is a 530hp Commodore,and despite being warned,my partner at the time set the cruise control whilst driving in wet conditions.Long story short,the left front wheel hit a puddle of water,the power came on,and she very quickly she found herself facing the direction from where she had come!  Only ever happened once though! Cheers

Thank you all for the replies, I especially appreciated those who kept on topic. Many thanks.

Regards.

Hetho.

Hi Hetho,

My son has a 2014 Toyota LC turbo diesel and he tows a van of around 3100kg.
He tows in selective 5Th unless, like Doug, the situation calls for another gear.
I have done one long trip with him from western Victoria to North Queensland and he uses cruise control only when the going is reasonably easy.
He has fitted his vehicle with a torque converter lock up kit to prevent the flaring from gear to gear that the Toyotas are common for of in standard form.
With the converter locked above 80 kph he manages to hold 5th gear without flaring and it gives him reasonable economy for the weight of the unit.
He has done about 100,000 Klms in the Toyota and although not all towing his transmission is fine.
He has a scan gauge and he monitors transmission temperature pretty closely when he is towing and the lock up kit manages to keep the transmission oil temperature much cooler than it did before the kit was fitted.
Before the kit he used 4th gear a lot mor than he used 5th and I should add that he tends to tow around the 90 to 95 kph speed.

To answer your question of should you change your driving technique I would suggest that while towing stay out of D and selecting either 4th or 5th all should be ok, but a converter lock up kit is not that expensive in the scheme of things and will improve both fuel consumption and vehicle driveability. The kit of course, would be your choice but a scan gauge that can monitor transmission temperature is something that would be very helpful.
My son by his trade, is a motor mechanic and he is also quite experienced in road transport and truck operation.
He also often quotes subjects from the Toyota Forum where they cover the subject of towing quite extensively.

A post on here is generally not even interesting without a rambling off topic rant so I might add my bit that while driving my little old Mitsubishi ute and towing in the hills my left leg gets really sore and aches and my cruise control cuts out when I put my foot on the clutch and I have to put fuel in it at daily intervals when I am towing distances but the revs remain high when I forget to change from third to fourth and I never tow in 5th because unlike a 79 series the overdrive in the gearbox is off the back of the box and will fail if used in this way and I never let female friends drive it in the rain just in case Mitsi misbehaves.

Now that is one big sentence without any punctuation or full stops so that should fit in quite well in the off topic section.

-- Edited by Iva Biggen on Tuesday 26th of November 2019 08:44:45 AM

Thanks Dougwe, Ivan and Trevor. I appreciate you comments and input.

Regards.

Hetho

Stretch60 wrote:

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Must be a land cruiser thing. My 2018 v6 diesel 8spd Amorok performs fantastic in cruise. With careful monitoring I never have it hunting between gears and sometimes assist in manual mode IF the gradient is very steep. Benefit of modern technology. Van weighs in at approx 2900kg.

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 We better leave this subject to Land Cruiser owners.

Our V6 Navara works well in cruise control 110000 kilometers  but on a reason inter state tour had a code come up on the dash which was not good. After several phone calls to various mechanical people, ie. Our regular service person, a respected auto guy, a friend of a friend and finally a Nissan Technician phones us back from Broken Hill. Ask a few question, gross weight of car and caravan? 5.5 tonnes, what gears are you using in the auto?, like "D" for drive I told him. He did ask a few more question, those were the main ones.

The S,,,,,,,t near come though phone and gave me the biggest dressing down. Short answer, drive the Navara in manual mode to 5th direct (our car is 7 speed auto). Now done 123000 kilometers and all good. Still maintaining around the 16 litres to the 100 ks.

Mamil wrote:

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Interesting discussion, and something I'd never thought about. My question is whether it's common across all autos for the torque converter to slip in higher gears, or is this problem specific to some models only? If so, what's the key to getting the torque converter to lock up, assuming I can't get an accessory torque lock up kit for my car? Thanks.

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 Many auto transmissions do not lock up if in D and are travelling at low speeds. Once a designed speed is reached they will lock up.

This condition is extremely variable between transmission types and even vehicle manufacturers. From what I understand the lock up function can be controlled by the cars computer to suit exactly what the manufacturer wants.

With the Toyota 200 series the earlier models from what I believe by my sons comments were notorious for not locking up until a speed which exceeded our National Highway limit so you were screwed with driving in D on say most of the Bruce Highway where the limit is only 100.kph.

When Toyota designed their car they werent much interested in the Aussie market because of its comparative size and it is only when clients started requesting that something be done was when they bought out a dealer modification.

Progressively Toyota have made their transmission work much better than say pre 2014 models and I do believe that the later ones can achieve lock up at a lower speed.

With many auto transmissions when you select a gear from the S range it will selectively lock the converter but again this is purely at the whim of the manufacturer. Their decision is based around a lot of variables, driveability and fuel consumption are probably the two most important.

Not many manufacturers care about their vehicles performance while towing even though most of them will be quick to point out that their model can tow 3.5 tonnes.

So in short we dont know what sort of vehicle you own but to drive in a selected S gear to suit road speed and conditions is much better for the transmission than to have it in D when pulling loads.

To Answer your questions yes it may be that an auto will slip in the converter in higher gears at lower speeds.

The best place for information regarding your particular model vehicle would be on a dedicated brand forum. My son uses the LCool forum which is abound with good information. This is generally better than most dealer workshop information unless you strike a good one.

If you let us know your vehicle type and model on here there is a good chance a member will have the same vehicle and offer good sound advice for you.

Not all vehicles need or even benefit from lock up kits as some manufacturers have them set to work in most situations.

Good luck with it, I hope this helps.

One thing to be aware of is that when you are accelerating from, say, 80kph, up to the speed limit of say 110kph using the cruise control some cars, like mine, use full, wide open throttle whilst others use a much more gentle approach. The full throttle strategy could be a real concern in slippery conditions. Fortunately the old Td5 is not a rocket ship..

Aqua planing is a pheromone only exhibited by rear drive vehicles, and mostly occurs after applying and releasing the brakes.

Theoretically if you drive long enough through water the front wheels will slow down start aqua planing, or if you have bald tyres. But tyre manufacturers design tyres to prevent aqua planing.

But even then the cruise controller only monitors driven wheels to set the speed.

And should the cruise controller ever try to increase the speed while aqua planing, torque would be applied to only the rear wheels.

Aqua planing affects steering and braking.

I have experienced the aqua planing effect in deep, new, wet, snow in Norway when the wrong grease was packed into the front wheel bearings and the grease dripped down onto the brake shoes and caused the brakes to seize.