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Captiva LTX Auto (2.0 diesel) 08 plate

I am going to make some assumptions to start with, the first being that the unused connector block under the back of the car (near the spare wheel) is supposed to be for thetow barelectrics?

If this is correct does it make any difference that my newtow barhas been wired into the car not using this block?

Next to throw into the arena ... could this be why my Captiva doesn't tow well in Auto but tows better when I change gear manually?

My theory is that the vehicle is unaware there is a caravan in tow because of the different wiring and therefore the Auto box is in some wayconfused... is this possible?

Look forward to your responses ...
 

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Do you get a green icon tow bar symbol on the dash when towing you still should.. The auto see's the torque required even if you had no electrics connected. something to look at,

Choosing a towcar transmission

A car's engine will not give of its best unless it is mated to a suitable transmission system to get the power to the wheels. Towing, in particular, places different demands on the car, and a gearbox good for solo driving may be less suitable when pulling an extra tonne or so.

A manual gearbox is simple and reliable provided the gear ratios are suitable for towing, but many users prefer the freedom and flexibility of an automatic gearbox, which basically does all the thinking for you and can make for relaxed driving. However, some types need modification for towing use if they are not to cause trouble. The latest semi-automatic systems are a hybrid between the two, can be used in a manual or automatic mode.

All-wheel-drive can be beneficial when trying to get off a muddy campsite, but it usually involves higher fuel consumption and adds another level of complexity. The right transmission system is always a compromise. Here we offer some advice to help you make the right choice.

Automatic gearboxes

towcar_transmission_in_contentTraditional automatic gearboxes (autos) include a hydraulic coupling in place of the clutch. A vehicle with one will use more fuel than an identical car with a manual gearbox because of inefficiences in the convertor and gearbox but you are spared the chore of using a clutch pedal and choosing the right gear and you won't be able to stall the engine on hill starts.

Towing with an auto is generally more relaxed than with a manual as the gears change automatically and driving in heavy traffic can be easier as a result. The disadvantages include heavier fuel consumption due to losses in the transmission, the need to keep the transmission fluid cool when towing by use of in-built or retro-fit oil coolers, and the higher costs of repair if something goes wrong. Some drivers also feel they are not in full control of what the gearbox is doing.

In recent years automatic gearboxes have improved significantly, particularly with full electronic management of the system that improves fuel consumption, adds a degree of manual control and provides a choice of many more ratios than previously. Six- and even seven-speed auto boxes are now common, which means the right ratio for more conditions and fewer losses.

In most automatic cars there are extra driving modes such as ""˜sport' and ""˜winter'. These alter the change points from one gear to another. ""˜Sport' mode allows better performance by optimising the vehicle for performance and can be helpful if you're towing in hilly terrain There are some systems that provide a ""˜towing' mode, sometimes on the more expensive models by detecting the trailer connection. ""˜Winter' mode starts the car in a higher gear and can help when pulling away on slippery ground, avoiding wheel spin. In short, modern autos remove many of the earlier drawbacks associated with this transmission.

Hill starts can be made more easily with an auto car as all you need is to release the handbrake while pressing the accelerator. The vehicle will supply sufficient power to get you under way without stalling or burning out the clutch. There are also hill-hold systems that will prevent the vehicle rolling back until sufficient power to move away has been put down. Once you get used to all this, reverting to an ordinary manual can be a real shock.

transmission_automaticThere are still some disadvantages to autos though. They are more expensive to buy, have more complexity and any repairs are best left to a specialist. The way the official fuel consumption and emissions tests are carried out do somewhat disadvantage automatics. Autos generally have higher CO2 figures, which can mean higher rates of car tax (VED). If the equivalent manual car is near the limit for its VED band for example, the choice of an auto box can push the car into the next higher tax band. It might not be that much compared with the price of the car, but you pay it every year.

One exception to letting the auto box do all the work is with downhill towing. In this case the engine will be at low revs as the gearbox senses that little power is needed. With an extra tonne behind, this can mean you will speed up faster as there is little engine braking to keep the speed in check. Downhill speed is one of the prime causes of instability in towed vehicles, and merely keeping the brakes on may result in the brakes fading on long downhill stretches. The solution is to manually select an appropriate gear (which all auto boxes will have) when descending, so that engine revs are kept up. If you are not sure about how to use this system, consult your handbook.

On the open road, automatics can largely be left to themselves in the D (or Drive) position. It can, however, be useful to manually select a lower gear when ascending a long hill, especially one where the gradient varies. In this case an auto box in D may switch ratios rather too often for comfort as it tries to find the best compromise. Using the hold allows the gearbox to stay in the chosen gear until the hill is past, and most users find this of benefit to the smoothness of the drive. Remember that there is also normally a ""˜kick-down' facility, which is useful when you need an extra turn of speed or power. Increased pressure on the accelerator will engage a lower gear at most speeds.

Long uphill stretches may also reveal another factor ""“ the transmission fluid can get very hot. This is not normally a problem as the car will have (or you may be advised to fit) a special extra oil cooler.

On- and off-site manoeuvring is made very easy with an auto, as long as you have a gentle right foot, ready to switch between accelerator and brake pedal. You may find it far simpler to get to the right position than when slipping the clutch on a manual box.

You need to be aware that manufacturers' maximum towing limits can vary from the manual versions of a given car. You need to check this carefully before you buy, as some autos' limits are lower than the equivalent manual car. Some are the same and some can even be higher. If they are lower, the maker's engineers usually quote ""˜cooling requirements' as the reason. In any case, even if the maximum limit will suit your caravan it is wise not to tow right up to the car's limit. Give yourself a bit of reserve capacity.

Towing limits

Whatever the car or its gearbox, the maximum towing limit set by the manufacturer is legally enforceable ""“ if you are stopped at a check, the authorities can refuse to let you carry on with the journey.

Always try to stay within the 85 per cent of kerbweight recommendation whatever the maximum quoted for the car to allow for difficult conditions and to get the best stability.

View our web page Matching Car and Caravan

Further information

Federation of Automatic Transmission Engineers:
list of automatic transmission repair specialists and information on cooling for automatics.
www.fedauto.co.uk

Vehicle Certification Agency (VCA):
comparison of current VED costs.


Semi-automatics

transmission_semi_automaticAlthough automatic in use, these gearbox systems are best thought of as electronically-controlled manual gearboxes with an automatic clutch. You can drive them like a full automatic, letting the electronics do all the work, or there is a fine degree of manual control, using an up-down lever, or sometimes paddles on the steering wheel.

A good example is the DSG (Direct Shift Gearbox) available in many of the Volkswagen Group vehicles. Here, there are really two separate but integrated gearboxes and two clutches. First, third and fifth gear are on one shaft and second, fourth and fifth on another concentric shaft. Two clutches control which of the gear sets is selected, and the change time from one to the other is very fast (as short as 8ms is quoted for an up-shift).

Other versions based on similar principles are used by Citroën, Peugeot, Ford and Volvo, all with slightly different names such as PowerShift and Geartronic, and all offer manual or fully-automatic gear changes. There is a cost penalty in higher initial price and greater complexity of repairs and it needs specialist transmission fluids. A semi-automatic is also heavier than a conventional gearbox (typically by about 30kg) although this can be useful when choosing the best towing match.

The advantages of this system is that there are far fewer losses from the system, which can offer up to a 15 per cent fuel consumption improvement over conventional automatic transmissions ""“ and can get very close to many manual gearbox figures. The changes are very smooth and extremely consistent, which makes for easy and relaxing driving. Manual control is a feature that can be engaged at driver choice, subject to the electronics' overriding control of an unsuitable selection. You can go up or down the gears at will with this, but you cannot ""˜skip shift' ""“ it has to be sequential. The automatic mode, however, can skip gears on its way to the best choice of ratio.

Another kind of gearbox is the Continuously Variable T ransmission (CVT). Most versions as used by Ford, Fiat, Honda and Nissan rely on variable diameter pullies for gear ratio variation and modern versions are much more robust and reliable than earlier attempts. All tend to sound a little different in use, which some may find disconcerting at first. There are other CVT systems in use in off-road applications that use different techniques, all aimed at seamless ratio changing and allowing the engine to be optimised either for economy or power .

All-wheel drive vehicles

transmission_4wdMany caravanners tow with 4x4 all-wheel drive (AWD) towcars. Often this choice is driven by the significant kerbweight available, so you can tow a larger caravan. Most have high towing limits, some even way beyond the kerbweight, though again the Club would advise sticking to the 85 per cent recommendation.

The main advantage in use is in traction off a muddy field or in snow. Driving all-wheels means power is spread over both ends of the vehicle, and the latest controls apportion the drive as traction becomes available, though skill is needed for best results.

There are different types of AWD systems. Some vehicles have permanent four-wheel drive, some let the driver select two or four-wheel traction (this can save fuel as fewer parts are being driven) and some do the job automatically depending on conditions.
 

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Discussion Starter #3
Thanks for this info ...

In answer to your first point .. No I don't get any dash lights when coupled up and towing, which I guess is because the official tow bar connection is not being utilised?

With regards the van its a good match, I checked this out on the Caravan Club website match report, I'm quite thorough with that sort of thing and have pulled reports off other websites too .. etc

My dealership recently changed a gearbox pipe which had a very slight leak and they suggested that under extra pressure maybe this was leaking more juice onto the exhaust?? and causing the towing issues, but I have not tried it since, maybe I will give it a tow this weekend round the block ..

I took my spare wheel out to clean it up and respray it,that'swhen I noticed the block connector all alone and doing nothing in particular which got me thinking ...
 

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Hi,

I know this is an old post, but still. I have the same issue as yours. I got an aftermarket tow bar and the official plug was not used. My catamaran is very light, around 150 kg. The trailer might be 300 kg. So its not that heavy. Would there be any issues wen towing with an automatic transmission?
 

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Why should there be? I can find nothing in the Owners Handbook to imply any issues in Automatic.
If you want to feel more in control with engine braking then use the manual option on the gearbox.
.
 

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Ed, the gearbox might have some sort of towing mode when the car knows a trailer is attached to it. If this is not the case and the plug next to the spare tire is only to have the towing dash light on, then its all good. I can live without it.
 

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Ed, the gearbox might have some sort of towing mode when the car knows a trailer is attached to it.
There is nothing mentioned in the Owners Handbook to this effect.
Just check max laden vehicle weight and permitted Trailer Towing weight and download at towing point. If necessary adjust tyre pressures as indicated.
You'll find this information in your Owners Handbook. If you dont have an Owners Handbook you can download from this Forum from the link I've previously provided.
 

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Thanks. There is nothing to worry then. I can live without the light on the dashboard.
 

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Update:

Towed my boat without any issues except for some overheating on a steep part of the highways when going 120 km/h. I guess this speed is too much for towing on a hill. It was not in the red, but a little bit before the red zone. I also noticed a weird thing - the arrow was not climbing / going down slowly, but its movement on the scale was rather chaotic. I read on this forum that overheating is common for these cars.
 

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Update:
I read on this forum that overheating is common for these cars.
Important to ensure that coolant antifreeze percentage mix is correct. Coolant antifreeze not only prevents freezing damage but it increases the 'boiling point' of the fluid.
Maintaining correct system pressure is important also.
.
 
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