Gearbox swap 2.2 ducato based motorhome (1 Viewer)

[knupz]

Hi all,


I own a dethleffs motorhome based on ducato x250 chassis equipped with 2.2 74kw 4hy engine with 5 speed gearbox. I’m happy how engine runs but somehow when cruising it may need the 6 gear since at 100km/h im at 2700-2800rpm and thats a little loud for my ears. Browsing the internet i discovered that same engine but with different code 4hu has 88kw and 6 speed gearbox and i was wondering if i could easily swap this gearbox with mine, anyone had experience with this engine? Many thanks

 

[TheBig1]

the gearbox may bolt to the engine, but the issues start at the drive shafts as they are unlikely to fit and a new pair may need making to transfer output to the wheels

 

[chatteris]

i think the 6 speed boxes were more unreliable than the 5 speeds

 

[Landy Andy]

What about changing your wheel tyre size to alter the ratios a bit ?

 

[knupz]

What about changing your wheel tyre size to alter the ratios a bit ?

I’m currently running on 225/65/16c. What do you suggest?

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[pappajohn]

225 70 16.....70 aspect is slightly taller than 65.
That will reduce revs slightly at the same speed.
Shouldn't affect Speedo readings not that they are that accurate to start with.

 

[Landy Andy]

I’m currently running on 225/65/16c. What do you suggest?

I don’t know. But altering my 215 15s to 225 15s made a difference to mine.

 

[Two on Tour]

I’m currently running on 225/65/16c. What do you suggest?

If you go from your 225/65/16 to a 225/75/16 it will increase your road speed at 60 MPH by nearly 4 MPH, so if you dropped back to 60 MPH with 225/75/16's, this would drop the engine RPM.
You could do a rough calculation of the RPM drop by noting the engine RPM at 65 MPH and then drop the speed to 60MPH to see if the drop in RPM is worth it.