# Manual Gearbox conversion for Merc Hymer ?



## 103394 (Mar 14, 2007)

Hi, I have a Hymer S700 with a merc sprinter 2.8 turbo engine fitted by the previous German owner 5 years ago, It has the original Auto G.box . On a recent trip to Austria, it felt like I need to either fit a manual G.box from the relavant sprinter or auto sprinter box (if their avaliable)
This is because it sounds like the engine is reving too high at motorway speed and i'm sure it could achieve better economy with the right box as it was designed to go with the original 2.9 non turbo engine.

I wondered if anyone has any experience/knowledge in this department ?

The engine code is DB OM 602 which i'm told by merc could be either from a 310 or 312 sprinter. (I can't get my head near enough to see engine number to get exact model)

Also could anyone recomend where to buy new gear box in the west country ?

Bart


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## vicdicdoc (May 14, 2005)

Maybe you could source one from a car breakers in your part of the country


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## androidGB (May 26, 2005)

Rather than change the gearbox, couldn't you change the rear axle ratio.

I would have thought that might be easier to achieve, and I believe they are supplied with differing ratios dependent on use.


Andrew


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## teemyob (Nov 22, 2005)

*Revs*

Hello Bart,

What are the RPM?

Ours is a factory fit Sprintshift on a 416 chassis. at 65mph ours Revs at around 3,100.

I believe this is due to the final drive ratio specified by MB along with very small wheels and tyres. Ours are 195/70/15

Trev


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## 103394 (Mar 14, 2007)

Hi

I'm told to ignore the rev counter as it's probably be lying, but its saying about 4,500 rpm at 60 mph ish.

Just did fuel consumption calculation from Austria trip. 
Over 3000km, it averaged 25km to the gallon (16 miles to the gallon i think) which is very poor i think.

So I'm sure now I need to do something to alter the gearing.

A friend suggested changing the diff. Any 1 have experience in this area ?
Doing it this way I could keep the original G.box.

Bart


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## androidGB (May 26, 2005)

bartx said:


> Hi
> 
> I'm told to ignore the rev counter as it's probably be lying, but its saying about 4,500 rpm at 60 mph ish.


But you said it sounded as it was reving too high.

Is there a chance that the box is not changing into top gear?

How many speeds does it have?

Are you able to change manually?

The people to talk to regarding auto boxes in the Bristol area are QAS in Filton (John) they were absolutely brilliant in even manufacturing parts for my daughter's Yaris as Toyota would only supply complete gearboxes (£2500)

Andrew

Andrew


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## 101405 (Oct 15, 2006)

*MERC GEARBOX*

This sounds as Android ses 4500 is far to high for top gear if there is no load on the engine!! have you checked the gearbox fluid is ok, and do you have it in its correct drive, do you give it time to change . Never ignore the rev reading in a diesel.


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## 103394 (Mar 14, 2007)

I think i should mention again my Hymer has the original auto box that was fitted back in 1993, which i assume is gear'd up to match the original 2.8 or 2.9 (I'm not sure which) non turbo engine.
It now has a Merc Sprinter engine, 5 cylider 2.9 turbo . engine code DB om602 which i'm told could either be from a 310 or 312 sprinter

I also thought it wasn't getting all 4 gears , but I can definatly count them. (I can change manually)
It gets through them very quickly, I'm in 4th at 30 mph

This is why i'm thinking the gear ratio needs to be lowered. maybe by changing the diff ?? Or fitting a sprinter manual box, but would have to be from a left hand drive to match my hymer.

I spoke to the dealer i bought it off and he advised me against fitting a manual g box as this would devalue it as most people want auto's.
Is this the case ?

feedback much appreciated

Ps what is "normal" mpg for this type of hymer ?


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## 106367 (Aug 9, 2007)

*manual gerabox for hymer sprinter*

Hi,
I own a 1984 hymer on MB309 basis,I would advise a number of possibilities,first forget the change to manual it's far too expensive it involves a lot of hours and hours cost .
You have almost certainly got a 312 engine since the power increase from standard 2.9L to turbo is only cost effective when instaling a 312 engine.
Check your import document as mercedes have a data sheet for every vehicle on which you should find the original engine and chassis numbers the gearbox type and number and contact with MB should give you the original diff ratios
first option check the tyre size uprating to for instance 205 instead of 185/195,if thats no go cos they are already max size then
a "longer diff can be fitted at reasonable cost There are various ratios available,you need to check theMB part number on the diff housing.
I had a longer ratio fitted to mine less than a day's work and part exchange for my old diff.
There is much info on various german sites ,if you can read german!
I do.If you need more info mail me.


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## 106003 (Jul 21, 2007)

get the torque converter checked out


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## ousty (May 14, 2005)

bartx
You did say what year your S700 was
I have a 97 S700 2.9 TD .It returns 22 M.P.G
Try driving at a steady 50 MPH & tell us what your revcounter says
then we can tell you if ???????????
ousty


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## merctoby (Jan 18, 2007)

*S 700 gear box do not change , try this .!!!!!!!!!!!!!!*

first of all , the mercedes you refer too is on a 410, chassis , !!
on this model auto and manual rev very hard even at 50, sounds like very noisy like you said loud . this the norm . for this model . the S 660 use, the same engine some are 2994cc- some are 2997cc, some are 2500cc. but are the the 5 cylinder configuration . 617 is all cast head and all , 602 is cast bottom end and alloy head . the turbo helps the engine get up to speed a lot qiucker . but still the gearing is still the same , it will not change. some people up the rear axle some people put the 814 bus mercedes gear box in but it is a bit sloppy . but it work,s . BUT thier is another way round this a lot cheaper too . i have the S660 on 410 chassis round 1989 your model could be up to 1995 , i think round this time they moved them out for newer model .1st i got the 16" wheels found on the 709 mercedes bus , put 215 tyres 215x75x16" , had to just shave the springs to allow tyre bulge they would touch springs otherwise , the old tyre size you are useing are the 185x14 c tyres or 195 . this tyre turns 1 whole circle of 79" now the 225x75x16" wheel and tyre turns 92" . next you take your merc to a dealer good fitter A GOOD FITTER ! and stretch the pump this is what you call ADVANCING of the pump , THIS WILL INCREASE POWER make the diesel leaner . now my merc used to do the same 16 mile to the gallon . now i get more speed less distance qiute no reving like mad and i have worked out now at 34 to the gallon . i did it . 

all the best denton , my model is the same as the avatar .!!


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