Automatic transmissions

[Mickymoody]

I think autos are underrated by the general public, but I don't mind them; sure overrun wears the front brakes down, but I just knock the auto into N when slowing. I also use 1 or 2 when cruising to give the engine a workout. When using an auto, you realise all the left footed work done, and how easy it can be.

 

[ericmark]

I think autos are underrated by the general public, but I don't mind them; sure overrun wears the front brakes down, but I just knock the auto into N when slowing. I also use 1 or 2 when cruising to give the engine a workout. When using an auto, you realise all the left footed work done, and how easy it can be.

That is against the law. You are not permitted to freewheel even though some cars were fitted with them. The last I saw fitted with freewheel was a mini although it was only in first gear hence why they say second gear to be used for long steep descents.
That is also something I had forgot. The Marina had a box designed so it would not change down until safe to do so engine revs wise so you could in an emergency slam it into low and it would give max engine breaking. However the Mini would wreck the engine if you did the same. So very important to read hand book.

 

[empip]

... Looking forward to any comments.
Cheers!
John

Best of luck with that ! You will get people telling you about their inside trouser leg measurements in a mo'
As they say down west... "S'rekon they buggers kin read, or wot??"

 

[Burnerman]

... Looking forward to any comments.
Cheers!
John

Best of luck with that ! You will get people telling you about their inside trouser leg measurements in a mo'
As they say down west... "S'rekon they buggers kin read, or wot??"

LOL nice one mate
As it happens, the unfortunate friends of mine now have an 07 Honda Jazz auto, (15k miles, ex motability) and I managed to get 2 years extra warranty on the deal - so hopefully they'll be trouble free for a while.
John

 

[Mickymoody]

I think autos are underrated by the general public, but I don't mind them; sure overrun wears the front brakes down, but I just knock the auto into N when slowing. I also use 1 or 2 when cruising to give the engine a workout. When using an auto, you realise all the left footed work done, and how easy it can be.

That is against the law. You are not permitted to freewheel even though some cars were fitted with them. The last I saw fitted with freewheel was a mini although it was only in first gear hence why they say second gear to be used for long steep descents.
That is also something I had forgot. The Marina had a box designed so it would not change down until safe to do so engine revs wise so you could in an emergency slam it into low and it would give max engine breaking. However the Mini would wreck the engine if you did the same. So very important to read hand book.

I don't understand when you say it's illegal to take a car out of gear - even when some cars were fitted with them? So what are you doing when changing gear in a manual, if not freewheeling? To use a manual car and change down, to use engine braking is useful, but an auto is constantly urging the car on, and thus making the brakes work harder in an auto, so brakes work better in an auto when in neutral, can't see how it's illegal to do so? Can you provide evidence of a conviction of taking a car out of gear, or what the law in this respect is?

 

[ericmark]

The law was to stop people free wheeling down hills with engine off to conserve fuel and was due to at the time the number of brake failures.

Back in 1950's free wheels were fitted to cars to help fuel economy but due to law this was stopped.

Not sure how it would be policed and the mini had a free wheel in first so was technically illegal but no one seemed to pick up on it so I would assume although there no one bothers any more.

The automatic does have engine breaking (Except for mini in first gear) but because it will auto change up unless you manually override many people don't know it's there.

Big automatics like the CAT 769 have a gear selector where the driver selects the highest gear and that way he can use engine breaking and some automatics are even interconnected with the brakes so first part of peddle engages engine braking the Lucas electric conversion as used with Bedford CF van was like this and it re-charged the batteries with first touch of brakes. The Toyota has copied this idea with their hybrid (Which is of course automatic). However there are loads of automatics and they are not all the same.

Many laws have changed for example when I first trained as an auto electrician rear guard fog warning lamps were illegal. Tail lights had to be between 5 and 7 watt and indicators and brake lamps 15 to 36 watt and 25 watt limit on reversing lamps. Now you have to have rear guard fog lamps so the free wheel law may have also changed. However I would not try it when on ones test!

As to "an auto is constantly urging the car on" this depends on the box and some do produce a positive torque at stand still but not all. And it is only at stand still or near that point once the car is moving they will ****** the car with throttle closed.

 

[j.m]

I think auto trans is brilliant ........ Ok its dearer to run than manual ....... But who sets out to buy a TV without a remote these days ? ....

The big deal with auto's is heat .......... If you don't know a little about how to operate one you can, well break em' PDQ....... I have a 97 Nissan Auto Trans unit that has covered 220K & is still going & going well It gets 4 Litres of Dexron 4 every 20K & that's it ........... I find it advantageous to keep taking up the slack in the throttle cable, hardly a massive engineering task & all is well.... (Ensures the kick down works properly)

In a similar vain, auto trans will not for a fleeting moment, put up with a badly running engine. Which I guess is where the two systems differ.

That is against the law. You are not permitted to freewheel even though some cars were fitted with them.........

Oh C'mon .......... Don't be a dick all your life PLEASE

 

[j.m]

As to "an auto is constantly urging the car on" this depends on the box and some do produce a positive torque at stand still but not all. And it is only at stand still or near that point once the car is moving they will ****** the car with throttle closed.

Two pedals ...... One makes it go, the other does the opposite..... Is this a difficult scenario ?

I press the lil peddle it gains speed
I Press the big peddle it slows down

I dunno bout you, but this is pretty cut & dried

 

[jetex]

Avoid the Vauxhall easytronic semi auto thing like the plague, they give loads of trouble.

 

[TicklyT]

.....I was always impressed that an auto can hold still on a hill, presumably this 'burns out the centrifugal' clutch, like in a manual car?....

Most are driven via a torque converter, so there is no clutch to burn out, centrifugal or otherwise. they just circulate transmission fluid between the pump and turbine of the torque converter, the same as they do at any speed.

 

[Burnerman]

Thats correct...doesn't half heat the fluid up though!!
John