Technical 2001 2.8 JTD 5th Gear Ratio

[Griff097]

I have looked through old threads but can't find the information I was looking for, has anyone got experience of reducing the 5th gear ratio on the 2001 ducato it's a Hymer motorhome so quite heavy and wont pull 5th up a slight incline or into a headwind, so you end up changing up and down 4th/5th a lot, it is like an overdrive ratio.

I have tried using Eper but can't get it to work at all.

 

[rolandbrindley]

It is just that, an overdrive for cruising on the level. It is an add-on to the 4-speed box and is out on the end in a separate casing, getting less cool oil that the main box, so it's a good idea to change down early on hills and let the engine revolutions do the work instead of heavy pulling. Best left as it is even if alternative gear sets were available which I doubt. How fast do you want to go in a caravan? I suggest 50mph is plenty especially in crosswinds.

 

[FreeSpirit]

Check this post from 2009, Essanjay at the time advertised on their website a lower ratio fifth gear for the 02-06 Ducato as to whether it fits your model?? but there seems to be no mention of it in their services section now so maybe all you can do is contact them to see if they can still source them.
https://www.fiatforum.com/ducato/203905-ducato-5th-speed-ratio.html
Cheers

 

[simonm]

It is just that, an overdrive for cruising on the level. It is an add-on to the 4-speed box and is out on the end in a separate casing, getting less cool oil that the main box, so it's a good idea to change down early on hills and let the engine revolutions do the work instead of heavy pulling. Best left as it is even if alternative gear sets were available which I doubt. How fast do you want to go in a caravan? I suggest 50mph is plenty especially in crosswinds.

I did the lower 5th gear ratio that Fiat offered in my 2003 model motorhome when I was also towing a trailer. It isn’t a case of how fast do you want to go, it more a case of wanting to use the top gear more often on a 4tonne plus vehicle.

The OP wants to reduce the gearing not go faster.

 

[rolandbrindley]

you could achieve the effect you want by altering the tyre sizes and maybe wheel sizes. This will change all gear ratios in the same proportion, which for a heavy van may be what you would want. I did that on my TD10 but discovered after I had bought 5 new tyres, with smaller rolling radius but somewhat wider, that the spare would no longer fit under the bonnet on the support provided, now it has to live on the bulk above the cab.

 

[Griff097]

you could achieve the effect you want by altering the tyre sizes and maybe wheel sizes. This will change all gear ratios in the same proportion, which for a heavy van may be what you would want. I did that on my TD10 but discovered after I had bought 5 new tyres, with smaller rolling radius but somewhat wider, that the spare would no longer fit under the bonnet on the support provided, now it has to live on the bulk above the cab.

Interesting alternative but the existing ratios are excellently spaced, 1st is very low and each takes over from the next beautifully without having to thrash the engine until you want top and even cruising on the motorway at 60 with the lorries, you go 4th, 5th, 4th, 5th, 4th, 5th, 4th, 5th, it's not a relaxed drive and until you get to 70/80 it doesn't want to pull it and that's not how I want to drive the van.

 

[simonm]

I agree with you there Griff. When I had mine remapped from 128hp to 158hp it helped a great deal but I was still dragging along 3.85tonnes without trailer. Adding the trailer and I was back to your 4th 5th 4th 5th situation.

I cured it in the end by getting a X250 2.3 6speed! But it cost me an extra £25k to do it ?

 

[GTYLER]

I did the lower 5th gear ratio that Fiat offered in my 2003 model motorhome when I was also towing a trailer. It isn’t a case of how fast do you want to go, it more a case of wanting to use the top gear more often on a 4tonne plus vehicle.

The OP wants to reduce the gearing not go faster.

Hi, most 5 speeds have a direct 4th gear with transmission directly through the shafts without using any of the selectable gears, 5th gear is often on the outside of the box under an end cover and does not get lubrication as well as the others. It is thus more efficient and causes less wear as well as breakage to keep the ratio as it is and change down. I have not taken my box apart, is it the same?

 

[Communicator]

Hi GTYLER,

This is an old thread, but welcome to the forum. Unfortunately your description of a direct drive in 4th gear does not apply to the Ducato, where the drive is indirect in all gears. There is threfore no decrease in gearbox efficiency between 4th and 5th gears. As has been posted, the problem of too large a ratio difference has been removed by fitting a six speed box in the x250 and later models. The 6th gear in the new box hs a similar ratio to the old 5th. Consequently the large gap between 4th and 5th has been removed.. A lower ratio 5th gear was an option on both x230 and x244 models, but does not seem to have been used on a regular basis.

For the benefit of anyone still interested in this subject there was an article relating to the modification on the x230 in the August 2012 issue (yes 10 years ago) of the MMM magazine. I have a copy of this article.

An alternative modification was developed by the Italian MH community, and described on their camperonline website. This Italian modiification uses a different 5th gear pair, and results in a 5th gear ratio intermediate between those offered by Fiat. It seems to have had enthusiastic response from those employing the modification.

 

[Gustav01]

I did the lower 5th gear ratio that Fiat offered in my 2003 model motorhome when I was also towing a trailer. It isn’t a case of how fast do you want to go, it more a case of wanting to use the top gear more often on a 4tonne plus vehicle.

The OP wants to reduce the gearing not go faster.

Did you change from the 53X31 gear ratio to the 45X33 ratio?