Automatic Gearbox?

[Wully]

Ive seen a few Hymers advertised with an auto box - are they very fuel thirsty / mechanicaly weaker or stronger that the manuals?
I’m loving my Beemer auto box..not sure it’s a good idea have an auto box in a MoHo..

 

[DBK]

There are different sorts of auto boxes. The ones fitted on Fiat Ducato based vans have what is in effect a manual gear box which changes gear itself. These are now fairly common in trucks because they can be very fuel efficient. Mercedes and some Iveco based MHs may have a more conventional torque converter transmission but they are much more efficient now compared to the old "slush pumps".

 

[Just smiffy]

I’ve averaged 31mpg over the last 3yrs and 30k miles with a 4.25t fiat 2.3 comformatic and no problems...

 

[pappajohn]

Modern full autos are very fuel efficient compared to years ago due mainly to the torque converter.
In the old ones the engine always revved higher than the gearbox input shaft because of the way the vanes moved through the fluid so more fuel was used.
New ones effectively lock up when the two shafts are at the same speed so really become the same as a manual.

The Fiat autos are a robotised manual gearbox operated by sensors, servos and actuators with the clutch being operated by the same.
It senses the road speed and torque then selects the appropriate gear.
It can probably change gear faster than you can.

 

[tonyidle]

I’ve averaged 31mpg over the last 3yrs and 30k miles with a 4.25t fiat 2.3 comformatic and no problems...

The Comfortmatic is a conventional manual with a conventional clutch. Just hidden from the driver .

Edit: posted after PJs contribution. Oops

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[StanandShirley]

Our Chausson 640 has an auto box it’s a Ford and works a treat silent gear changes and very lively. As we have only done 400 miles I have to remember to slow it down as it wants to take off very pleased

 

[Shropshire lad]

I have had MH’s with both types of auto box. I now drive a 4.25t MH with the Mercedes auto and it is superb! Relaxed driving and economy pretty much the same as a manual.

 

[tonyidle]

I have had MH’s with both types of auto box. I now drive a 4.25t MH with the Mercedes auto and it is superb! Relaxed driving and economy pretty much the same as a manual.

I love mine!

 

[Tykatem]

I've owned BMW's for over 25yrs all of them have been automatics. I have a 2012 Hymer weighing in at 4.2t based on a 2.2 Mercedes with automatic box and I love it. There's no loss of power and I get around 30 mpg. It can also be used manually in selecting the gears yourself.

Pete

 

[ctc]

Auto box and cruise control, 11.3lt/100k. Van weighs 5.5t. Using my foot 14lt/ 100 at best.

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[tacr2man]

Full autos are very useful in maneuvering loaded M/H gently in close confines , self-changing gearboxes show up their weakpoint in such situations, and can overheat or damage themselves if not careful , much like a normal gearbox with driver who has poor clutch control .

 

[Guigsy]

I've driven a few cars with robotised manuals or dual clutch boxes. In normal driving, they are pretty comparable to a torque converter auto.

When doing slow speed manoeuvres though, they can be a bit cumbersome. As @tacr2man said, it can feel like you've got poor clutch control. They can't decide whether you want to slip the clutch at the biting point, or pull away. I can imagine that climbing levelling ramps would be interesting (not that it's easy with a manual either).

 

[Lenny HB]

Fuel consumption not worth worrying about with a motorhome.
Our last two Hymers have had Comformatic boxes more economical than the manual, not had any problems with them, certainly wouldn't go back to a manual. Get around 25 - 26 mph which for a brick on wheels is pretty good.

 

[funflair]

Auto box and cruise control, 11.3lt/100k. Van weighs 5.5t. Using my foot 14lt/ 100 at best.

I make that 24.9 mpg

Martin

 

[Wully]

Thanks folks!

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[gus-lopez]

I make that 24.9 mpg

Martin

& 20.26mpg the other.

 

[funflair]

& 20.26mpg the other.

I didn't see the other figure, I get 20.107 so close, ours is in Km so I just use Km/litres x 2.815 for the conversion as it saves converting Km to miles and litres to gallons every time.

Martin