Automatic Gearbox? (1 Viewer)

Wully

Free Member
Jan 7, 2019
98
249
Funster No
57,882
MH
Hymer B524
Exp
Godot was inspired by the DVLA
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

LIFE MEMBER
Jan 9, 2013
18,074
48,366
Plympton, Devon
Funster No
24,219
MH
PVC, Murvi Morocco
Exp
2013
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".
 
May 31, 2015
11,802
45,074
Cornwall
Funster No
36,638
MH
Ducato PVC
Exp
Getting Better
I’ve averaged 31mpg over the last 3yrs and 30k miles with a 4.25t fiat 2.3 comformatic and no problems...
 

pappajohn

LIFE MEMBER
Aug 26, 2007
43,428
50,237
Dark side of the moon
Funster No
172
Exp
Since 2005
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.
 
Aug 6, 2013
11,963
16,583
Kendal, Cumbria
Funster No
27,352
MH
Le-Voyageur RX958 Pl
Exp
since 1999
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 :D.

Edit: posted after PJs contribution. Oops

Subscribers  do not see these advertisements

 

StanandShirley

LIFE MEMBER
Apr 29, 2014
415
491
Chatteris Cambridgeshire
Funster No
31,226
MH
Chausson Titanium 640
Exp
four years
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
 
Jan 16, 2017
149
123
Shropshire
Funster No
46,928
MH
Coachbuilt low profile
Exp
Since 2016
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.
 
Mar 16, 2016
1,072
6,601
Norfolk Riviera
Funster No
42,019
MH
Hymer S520
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

Oct 12, 2015
1,533
2,569
Crowle
Funster No
39,408
MH
Hymer b680
Exp
New
Auto box and cruise control, 11.3lt/100k. Van weighs 5.5t. Using my foot 14lt/ 100 at best.

Subscribers  do not see these advertisements

 
Oct 2, 2008
4,522
8,134
Salopia
Funster No
4,247
MH
Duro 6x6 Overlander
Exp
since 1968
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 .
 
  • Like
Reactions: DBK
Sep 17, 2017
5,610
10,489
Birmingham, UK
Funster No
50,575
MH
A-Class
Exp
2017
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

LIFE MEMBER
Oct 18, 2007
54,067
152,563
On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
:welco:

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.
 
OP
OP
W

Wully

Free Member
Jan 7, 2019
98
249
Funster No
57,882
MH
Hymer B524
Exp
Godot was inspired by the DVLA
Thanks folks!

Subscribers  do not see these advertisements

 

funflair

LIFE MEMBER
Dec 11, 2013
19,518
31,078
Guisborough
Funster No
29,351
MH
MORELO palace
Exp
since 2012
& 20.26mpg the other.
(y) 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
 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Log in

Already a member? Log in here.

Latest journal entries

Funsters who are viewing this thread

Back
Top