Auto versus DMF?

To be honest I find towing with an automatic easier, anything with a decent towing capacity has an oil cooler anyway. Higher fuel consumption isn't a given, my old Granada auto got better figures than the manual. Equally if you're looking at the cost over 80000m then DMFs aren't that expensive

But at around £1k to replace, the dilema is how many times will you have to change it. There does not appear to be any pattern to the failures, it could last 30k or it could last 150k, that is the gamble.

Personally I think I would also prefer an auto for towing vs one with a DMF, of course it depends what size of towing vehicle you are talking about. Towing with a 1.6 Focus is not quite the same as towing with a

4.0 Discovery

Wife has an isuzu auto which we use for towing the caravan. So easy compared with the old manual 4 x 4 we had before

Have been easy to drive in the current weather as both have Winter mode options on the boxes and will amble along without touching the accelerator on the really slippy bits

It would appear than some autoboxes are a nightmare. For example I was warned off of Audi when buying the Volvo as the autoboxes are dodgy (on a

54plate) unrepairable and not economic to replace

Some friends with DMF vehicles are replacing with solid flyweel conversions at first clutch change, cheaper to buy and no bits to fly around and cause collateral damage when they wear out

Tony

I've used autos for towing (big twin-axles) for years now - they do the job far better as there's no loss of drive as you change gear - just kick down on that hill! A fully-loaded Previa with a fully-loaded caravan is still perfectly capable of accelerating, even uphill, at the legal speed limit. I've never had any gearbox issues with any of the two Mercs and three Toyotas that I've used. All but the 4runner were well over 130k miles. I wouldn't buy another manual towcar (I do tow with my manual VW camper but I didn't buy it for that!)

Oh yes, and I did once have a manual Previa too. Fuel consumption was about the same.

You only hear of the ones that fail. You never hear of the 100,000's that do over 100k miles without failing.

Mine is on 130k now and showing no signs of problems.

Longevity probably depends on the make and type of box. I have 2 Auto BMW's, Both with around 190k, and their original boxes are still working perfectly.

A point to bear in mind, is that unless you really try, it's difficult to abuse a relatively modern auto box. You can't over-rev it or crash the gears, so on the whole, an auto box would appear to have an easier life.

I've towed caravans with both types of boxes, and given a choice would always choose an auto over a manual box..

A no brainer to me, as I'd always go for an auto box rather than any manual, and AFAIK most larger autos suitable for towing have oil coolers anyway. . Plus the difference in fuel consumption of a modern auto versus an equivelent manual is quite small. Too small IMO to outwegh the advatages of driving an auto on todays congested roads. Mike.

" Thanks to everyone who chipped in.

I'm leaning towards an auto, will give it some more thought.

Your input was helpful and appreciated.

Cheers

I replaced mine at 120,000. It hadn't 'gone' but was making a noise and I didn't want to get let down all of a sudden. I reckon it put 1p a mile onto my motoring costs.

Rob Graham

Spanx has brought this to us :

Not necessarily, I'm aware of boxes having done 200K without an issue and the engine tends to have an easier time with an auto.

I use an auto to tow with and it works fine.

The autos consumption seems to improve slightly whilst towing. I think DMF's seem to mostly give problems on cars that are thrashed by their owners.

As an aside, have autos 'normalised' now days?

I've had 3 autos so far (but all a good while ago) and were all used for towing but only smaller stuff (boats, 1/2 tonne goods trailers etc).

The first was a 1300 Mk1 Escort and that felt like it was engaged (driving) all the time.

2nd was a Corsair 2000e and that was quite nice, didn't drag at tick over and the drive felt fairly positive (and we used to tow a 16' bilge keel sailing cruiser with that). 3rd was a Vauxhall Victor 1800 and that felt like it was propeller driven! ;-)

The only other true auto (multi gear rather than 'variomatic') was a Honda C50LA (step through motorbike) that had a three speed auto box using a series of centrifugal clutches to manage the 'auto' bit (and that actually worked very well).

Cheers, T i m

With the exception of some of the small auto boxes, they are still torque converter driven and still have an element of pulling all the time. new boxes are all computer controlled and have many more ratios built in. the most confusing one I drove recently was a very late mondeo diesel auto, I was rolling down the lanes and approaching a thirty limit, so I released the accellerator and expected it to just go a bit quieter from the engine and roll the speed off slowly as per every auto I have ever driven (lots) instead it changed down for itself and slowed the car significantly. I assume this is so that it will pick up well when needed (narrow power band) but was not actually what I wanted it to do, I prefer it to change down when I start to accellerate as per 'normal' autos !! Nicest recent auto box (IMO) is on the late Lexus range, some have 8 speed transmission, changes are almost imperceptable.

Ta.

Yeah, I saw that mentioned somewhere. Not like the old 3sp B&B box in the Corsair then. ;-)

Oooerr. In my ex FILs Daffodil you at least had to pull a choke-like knob out of the dash to get engine retardation. ;-)

Indeed. I think some of the new / bigger scooters have manual override of the variomatic 'box' (that's even weirder than a box with actual gears [1]). Even sport and economy modes.

Heh.

I bet! I recently restored a Yamaha YP250 scooter and I'd not ridden a 'Twist n go' scooter that big before. From about 10 mph it's like sitting on a weird catapult ... the revs don't seem to do much but the speedo just keeps climbing (well to 60 anyway). ;-)

Like you I'm not sure I like the lack of predictability on the overrun though (at slow speeds the centrifugal clutch drops out and you then just coast).

Cheers, T i m

[1] The transmission ratios are controlled by sliding 'V' pulleys on crank and final drive i/p and a rubber belt between. As the revs go up the crank pulley closes, increasing the diameter of the pulley and reducing the one at the rear. I think one / some of these new big scooters (600+ cc) can hold the pulleys at particular stages, giving the effect of locking it in one gear, hence making a fully variable ratio transmission into a mock 'geared' one? ;-(

My Dad had a Volvo 440 that had CVT that worked in that way, and yes, that would do the static revs thing while the speed climbed. IIRC it had a torque converter in front of the CVT.

Incidentally, DSG represents a different approach to the normal TC/Epicyclic auto, with 2 computer-controlled clutches and a automated synchromesh box. I think Ford do a version now, as do Porsche (they call it DPK). DSG has less pronounced creep than most.

MG/Rover did that with what they called 'steptronic' in the MG TF, as, IIRC did Audi with Multitronic. The Audi version is a bit unloved and unreliable, as was the Ford CVT, and the Nissan Micra one, I believe. I don't know what the MG one was like, but what are the chances?

That would be Multitronic then.

Very true. I've had 4 diesel cars with DMFs (one from new to 70k miles) and had no problems. As with clutches, some failures are due to abuse.

Those had a conventional looking clutch that engaged as the revs increased, I actually changed one !!! And put a set of belts on it. When that system came out on the DAF variomatic someone put one in for hillclimbs and won! they banned it !

The old Dafs had a centrifugal clutch. I had to change one and the drive belts, which was a real PITA job. When Volvo took Daf over they recognised that the clutch was the weakest point in the system and as you say they installed a servo driven conventional clutch. It much improved the car, but cars like the 440 ended up with a very heavy body on a transmission that IMHO just wasn't up to the job.

"GB" gurgled happily, sounding much like they were saying:

Umm, the 440 was conventional east-west FWD.

I suspect you mean the 340 - and most of them didn't even have the "variomatic" CVT, but a perfectly normal manual box. The only "odd" thing about the 340's transmission was that it was located at the back of the car in a transaxle. Just like a Porsche 944 or Alfa 75.