Letters reproduced from MMM March 2007.

It may be summarised that whilst the problem of failure of fifth gear is a 'known issue' in the trade it is by no means universal. If the failure rate is indeed close to 1 in 50 vehicles, then it is something that Fiat should be ashamed of - but as can be seen by their response to the different problems with their more modern X250 chassis (produced from c 2006) their customer satisfaction index leaves a little to be desired.

Some failures may be due to harsh treatment of the gearbox by owners - something that a more robust unit would be better able to withstand. The following letters and responses are reproduced as a part of the public record.

FAILURE OF FIFTH GEAR: ONE

I was travelling back from Pembroke when the gearbox suffered from Fiat-itis - the gears kept jumping out of fifth. When I got it home (in fourth: rather heavy on the fuel!) and with all of 37,000 miles on the clock, my mechanic said that he wasn't prepared to fit a new fifth gear housing without stripping out the gearbox first, just in case I had done serious damage due to the distance I had driven.

Consequently I have just had a bill for £1400! But looking on the positive side, the work did include a new clutch, so I shouldn't be picky (should I?).

Yet another instance to add to my thirty plus file of Fiat Ducatos suffering fifth gear failure prematurely. It seems these failures are not all the same. In same cases the driving gears wear or break, in others it is the synchromesh mechanism that breaks up. Some are highly reliable and I know of one unit with 250,000 miles under its belt.

I now have our Marketplace Editor, Barry Crawshaw's, set to examine and photos of a few more. It seems that one of the most common ways is for the synchromesh teeth to break off the driver gear but instances of these teeth suffering excessive wear have also occurred. Superficial examination of the one I have to hand leads me to suspect poor heat treatment of the gear but other factors cannot be ruled out. I understand driving gear wear may be related to low oil level and that fairy early in the Express era a modified dipstick with higher marking was adopted, but I do not have precise details.

I can understand a mechanic wanting to strip the main gearbox to be sure there had been no damage, but in the light of what I now know I would insist that this decision only be made after stripping the fifth gears to check the nature of the problem. The pair of fifth gears are easily accessible as they are mounted outboard of the main gearbox inside a separate pressed steel cover Normally the entire job, including parts and labour costs less than £500. The gear I have seen had only lost a small number of very cleanly snapped off synchromesh teeth. If these could be accounted for further damage is highly unlikely.

One photograph I have been sent - of a very badly damaged gear with several helical teeth smashed or missing - may have occurred when synchro teeth fell into the helical gears, and it is pure chance if this happens, or if the synchro teeth are thrown clear to fall harmlessly to the bottom of the fifth gear cover. Owner reports indicate that where only the synchromesh mechanism is damaged the gear suddenly starts jumping out or fails to engage, but if driving teeth are damaged there is at least a short period of, and sometimes ongoing, horrible grinding noise. If the latter happens stop and seek help immediately, as nasty hard bits of metal are contaminating the lubricating oil and are likely to cause very expensive damage. I know of several instances where, like you, owners have risked limping several hundred miles home even from the Continent in fourth gear without apparent further damage.

The prospect of several days' holiday disruption while waiting for fifth gear to be repaired no doubt spurs many an owner into bashing on regardless, but it might be prudent to first get a local garage to take the cover off for examination before deciding what to do. If I had a Sevel 1 would seriously consider disturbing the wallet moths and buying a spare set of gears and can of gear oil to carry. Then I could change it myself, or if desperate, take the parts to a convenient garage. Commiserations on having joined a not particularly exclusive club. GC

FAILURE OF FIFTH GEAR: TWO

1998 Swift Kon-Tiki

I have a 1998 Kon-Tiki, and fifth gear has failed twice in five months and 4000 miles. I know this has been the subject of several articles, and I would appreciate any feedback from yourselves or readers as I am considering taking Fiat to the small claims court for the cost of repairs.

Before rushing into a legal action against Fiat for repairs to your fifth gear here are a few factors you might wish to consider. Over the last twenty years Fiat have provided the basis for about 60 per cent of European motorcaravans. At a guess there are anywhere between 30 and 45 thousand in the UK.

MMM currently sells in excess of 30,000 copies per issue and perhaps around 15,000 readers have Fiat based motorhomes.

I have been editing Interchange for the last nine years and have a file of just over thirty letters from readers who have had the problem. One or two report that, like you, the fault has quickly reappeared after replacement. One could reasonably expect a high degree of under reporting but even if only one in ten bother to write it only happens to one vehicle in fifty.

The transmission repair trade is familiar with the problem, and many keep the gears in stock. There are numerous theories as to why some gears fail. They include:

Lack of lubrication due to:
Oil drain off after long periods standing unused
Insufficient supply from main gearbox
The transmission is an elderly design operating right at the limit of its designed torque capacity. It was replaced by a new unit in 2002 and there have been no reports of failure in this later unit, (though, of course, early failures would have been dealt with under warranty).

The unit in the new (2006 and onwards) models is totally different A quick check of its nether regions revealed there is no pressed steel fifth gear cover. I have yet to see internal arrangements, but it may well be that all gears are now inside the main case and fully supported by bearings at both ends of the shafts. This would be a better engineering solution than the previous arrangement with the fifth gear set only supported on one side.

Patchy quality control of components or during assembly.
Drivers changing up too early and or down too late subjecting the transmission to severe engine vibration. (Over reading speedometers could also mislead mechanically unsympathetic drivers.)
A combination of some of the above.

I have written to Fiat about the matter and their reply is that they have no dealer service feedback to indicate the problem is widespread, but it would be interesting to see their figures for worldwide sales for the replacement gears. The answer is no one, except perhaps Fiat, fully understands the problem and commercial considerations make disclosure by them highly unlikely.

Sue if you wish, but take legal advice first and remember that if the case is defended and you lose, the other side's costs can be awarded against you. Mechanics, although expensive, come cheaper than lawyers. GC

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