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Most modern rear brakes are adjusted by the footbrake;h/brake adjusted ones are very old technology.
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Why does a parking brake need to be applied at a junction in an automatic if P is engaged? imo P is far more reliable and efficient than any parking brake!
At a junction, I'd leave it in D, with my foot on the footbrake. Parking brakes aren't required on an auto, because P locks up the gearbox. Is still good practice to pull the handbrake on when you park though, because next time you drive a manual, you might forget! ;-)
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At a junction, I'd leave it in D, with my foot on the footbrake.
Is this why so many cars these days seem to sit on the footbrake at junctions/traffic lights?
I have found this an irritation as I - not always - try to apply the handbrake to avoid dazzling the driver behind. However I am switching cars soon and getting an auto, so will be learning a new way of managing these situations. I will be interested to see what is the majority view.
Regarding being hit from behind, might it cause serious transmission damage if you were in P, rather than D or N with the brake applied?
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Is this why so many cars these days seem to sit on the footbrake at junctions/traffic lights? I have found this an irritation as I - not always - try to apply the handbrake to avoid dazzling the driver behind. However I am switching cars soon and getting an auto, so will be learning a new way of managing these situations. I will be interested to see what is the majority view. Regarding being hit from behind, might it cause serious transmission damage if you were in P, rather than D or N with the brake applied?
The whole point of an auto is that you keep it in "Drive". It's not an auto if you have to move the gear selector even once when you're driving. Most people in Australia drive autos, and I've not yet seen anyone over there apply the handbrake whilst driving. Nobody over there whinges about dazzling brake-lights either....considering they're only 21W bulbs, and the headlights of cars approaching you are about 60W, I don't really think dazzling is an issue (I certainly have never felt dazzled by brakelights either in the UK or Aus). Also, I think transmission damage would be the least of your worries if your car was mangled by the vehicle behind, I don't know why on earth anyone would have their car in "Park" unless it was parked.
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Why does a parking brake need to be applied at a junction in an automatic if P is engaged? imo P is far more reliable and efficient than any parking brake!
Shifting into P at every junction would be very tedious - you would also be going through 'R' every time thus flashing reversing lights at the car behind and wearing the box.
By leaving in D and pulling on the handbrake you have a little additional safety (e.g. if you were shunted from behind or you foot slipped off the brake pedal then the parking brake limits how far forward you would roll).
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I'm with Aprilia on this one, Using Park at junctions and lights is not the way to go the parking brake is a far more sensible solution. Sitting in Drive with your foot brake on is ok for short stops but at lights and the like this is not good practice. If you are shunted in the rear your foot comes off the brake and the car runs forward as it is in drive, by the time you realise you may have traveled into the path of another car. I recall a story, and it may just be that, where a driver was first at a junction and was not concentrating the guy behind peeped his horn and the driver applied lot of revs but he forgot he was in Park, in his panic he pulled the selector back but due to the high revs as he went through reverse the car leapt back and hit the car behind. The use of the PArk function should not be used to secure the car on a slope as this puts a high preload on the Box and can lock the box, or make it very hard to get it out of Park. Always use the handbrake, secure the car then engage Park. Regards Peter
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From the MB W124 manual:
When stopped for a short time (e.g. at traffic lights) leave the selector lever in the drive position and hold the vehicle with the service brake. When stopped for a longer time with the engine running, put the selector lever in the N position. Use brakes, not accelerator, to hold the vehicle on slopes. Thus, unnecessary heating of the transmission can be avoided.
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The MB manual sounds fair enough to me - I'd only put it in neutral after 10-15 mins though. May as well buy a manual if you're going to visit "P" every 5 minutes. My mum only has autos, and even the old Montego she had about 10 years ago got up over 100k on the original 4-speed autobox (Honda unit perhaps? ATF was never changed either). Being an Aussie, she drives without the handbrake, and only takes it out of D when either going backwards or parking. Has never caused any issues with durability - she's just got rid of a Vectra, and the autobox is the only part that hadn't broken at some point!)
In my (fairly limited) experience, autoboxes are very strong and rarely break, provided they're not made by Renault or Ford. Don't be afraid to abuse an autobox slightly, they're not that fragile! Drivers certainly abuse manual transmission (crunching etc), and manual box failures only usually occur when the car's ready for scrapping anyway. Likewise with a decent autobox.
Looking around, most are now made by Jatco, Aisin or ZF, all of whom seem to know what they're doing. Jatco is part of Nissan (puts boxes in Nissans, Suzukis, Hyundais, Kias, Mitsubishis, London Taxis etc), Aisin is part of Toyota (and supplies GM and Porsche), and ZF puts boxes in VWs and BMWs, recent Fords, and Peugeots/Citroens.
Aprilia's the man to talk to about Autoboxes, and I'm sure he'll tell you they can take a hammering.
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Looking around, most are now made by Jatco, Aisin or ZF, all of whom seem to know what they're doing. Jatco is part of Nissan (puts boxes in Nissans, Suzukis, Hyundais, Kias, Mitsubishis, London Taxis etc), Aisin is part of Toyota (and supplies GM and Porsche), and ZF puts boxes in VWs and BMWs, recent Fords, and Peugeots/Citroens.
JATCO and Aisin-Warner are spin-off companies from Nissan and Toyota, respectively. They operate independently.
Mitsubishi, Hyundai, Kia and Proton all use transmissions originating from Mitsubishi's Diamondmatic division.
GM are big supplier of auto's of course, not just to GM cars but to Volvo, SAAB, BMW etc etc.Aprilia's the man to talk to about Autoboxes, and I'm sure he'll tell you they can take a hammering.
Not sure what you mean by 'a hammering'. Auto's usually last the distance unless they are abused. Keeping them in good condition means regular fluid changes. Heat is the big enemy of automatic transmissions - keep the temp down and the box will last a long time. If you have been towing in the summer and get caught in a motorway traffic hold up on a hot day then knock the transmission straight into 'N' - it will thank you for it. A extra-large transmission oil cooler can also help prolong transmission life.
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A lot of Fords use Jatco.(Japanese Auto Transmission Co.).The BW35,Ford C3/4 were good gearboxes;reliability on all makes of auto transmission went down when they tried to squeeze in more than three ratios.Volvo is part of Ford.Saab is part of GM.
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A lot of Fords use Jatco.(Japanese Auto Transmission Co.).
Possibly the link with Mazda? Ford in Europe seem to use ZF boxes, as the Sierra and Mondeo proved that they were incapable of building their own 4-speed box that lasted 100k. I've recently read somewhere that the Focus uses a Jatco-based box, which Mazda have tinkered with.
Looking at the Haynes manual for my Almera, both the manual and automatic versions require a gear-oil change every 36k. We used to have a 1977 MkII escort auto that ran for 60k, over 10 years, on its original ATF. Never did any harm, because the car ran up till a couple of years ago when the Ford bodywork fell to bits. Like engine oil changes, if they're done on time all should be well - if they're not, you're taking a chance which may, or may not, have an effect on the life of the autobox.
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Mitsubishi, Hyundai, Kia and Proton all use transmissions originating from Mitsubishi's Diamondmatic division.
Read somewhere that had been bought by Jatco?
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A 1977 Mk.II Escort was fitted with a BW35 which agrees with what I said.
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What's all this about not touching the selector lever once it's out of park? Autoboxes aren't a magic way of operating the vehicle, just a way of automating gearchanges when on the move. I always slip into neutral and use the handbrake (if necessary) if I'm stopped for more than a few seconds in traffic. There's no need to go in and out of park but it seems sensible to me not to let the fluid heat up unnecessarily by straining against the brakes half the time.
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it seems sensible to me not to let the fluid heat up unnecessarily by straining against the brakes half the time.
Some auto's drop themselves into a neutral gear if the gearbox senses the brake lights have been on for a couple of seconds and the box is still in D. My previous Vectra-B & current Vectra-C do this.
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Some auto's drop themselves into a neutral gear if the gearbox senses the brake lights have been on for a couple of seconds and the box is still in D. My previous Vectra-B & current Vectra-C do this.
Is there a noticeable delay, when the lights turn green and you take your foot off the brake, for the box to select 1st?
I'm surprised MB's boxes don't do this. My C270 pulls strongly against the brake at rest - I really have to press hard on the foot operated 'hand' brake to hold the car if it's in gear.
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Is there a noticeable delay,
In the case of my Vectra gearbox, it's pretty much instant. Foot off brake and it's back in gear.
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In the case of my Vectra gearbox, it's pretty much instant. Foot off brake and it's back in gear.
Having driven a Vectra B auto, Dave's absolutely right. You hear the engine note change once you're stationary with foot on brake, and as soon as it's released, the car takes a fraction of a second to begin moving forwards. I'm sure a lot of recent autos do that (Toyotas may well share the gearbox as it's an Aisin one I think). I find it very hard to believe that the level of heat produced in a 30-second stop at the lights would cause any damage to the gearbox anyway.
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Most Vauxhall autos select neutral when stationary with footbrake applied, certainly my Astra Mk4 does. The re-engage is almost instantaneous - a noticeable delay if you're trying to emulate Mr Schumacher, but not really noticeable otherwise.
The IAM is having to re-think it's advice about not using footbrake at junctions to avoid turning autos into manuals. In reality, if a high-level brake light dazzles you, you've probably stopped too close to the vehicle in front!
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