# fiat weak 5th gear



## icer (Dec 11, 2006)

Just about finished this question when blo*dy computer decided to restart itself to install updates!!!!

Here I go again.

I have been searching this forum with reference to the suggested weak 5th gear problems with the fiat engine..

I have been unable to determine exactly which engine types are affected. some say 2.5 non td other 2.5 td and the jtd version.

my own vehicle had a 2.5td ( i or s ) dependant on where I look.

Reportedly I should not use 5th gear before the engine warms up and should not use it below 50Mph?80Kph.

This speed is ok for motorway use, but when using it on provincial roads the engine note is telling me to change up at say 70~75 kph and quite honestly behaves impeccably

I don't have a tachometer fitted so do not know engine revs.

I am aware that it is possible to have a higher ratio 5th gear added, but I may already have one. 
How can I tell? 
with a prop shaft you could count the ratio between wheel revs and prop rotations.

As there has been so much discussion on this subject in the past does anybody have a definitive answer as to which vehicles / engines are prone to this problem.. Engine Numbers!

I would be glad of any information you can give me.

Hymer E650 1997 It was plated at 4000kg when built

ian


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## Pusser (May 9, 2005)

I don't know hardly anything about this level of mechanics but what I do know, speaking as an idiot on these subjects is that since I have Van Aarken'd, all my gears work absolutely spot on.


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## wakk44 (Jun 15, 2006)

hi Ian,

I have the 2.8 jtd with the high ratio 5th gear.It is fine when cruising on the motorway,but unuseable below around 45mph unless you are going down a long gradient.I personally don't regard it as a problem in fact it is preferable and more economical for motorway driving.

No idea about engine no's fitted with this 5th gear but you will know if yours is because you will have hardly any torque at 45 mph and have to change down.

Steve


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## teensvan (May 9, 2005)

Hi Ian.

The two main reasons why the 5th gear fails is 

1) the oil has not had enough time to get to the 5th gear cluster always let the engine warm up about 6-7 miles.

2) A lot of drivers let the RPM drop to low and then put there foot down this causes a lot of strain on the small 5th gear. You should not drive slower than 50 MPH in 5th unless it is on the flat. We had our 5th gear lowered and can now drive at 40MPH in 5th and the engine still pulls ok. This now works a lot better for us as we do not do all our driving on motorways.

steve & ann. ------ teensvan.


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## icer (Dec 11, 2006)

steve & ann

As an aside what was your maximum top speed before and after your 5th gear was lowered?

Secondly where did you have it done?

I gather you are more than happy with the result.

My issue is that I was told that 80kph is the minimum speed to viably use the 5th gear or it could cause damage to the gear. 
In practical terms and I used it for the 1st time at the end of march, We went to France ,Belgium, Luxembourg & Germany, on the minor roads traffic speed was say 75kph and keeping it in 4th seemed like the engine was overworking and realistically I would at that point change to 5th.
when I did there was no problem, and the engine did not labour. I have pushed it in 4th gear and have got to 85 kph before changing.

My dilemma is do I ignore those out there who advocate never below 80 kph or change the 5th gear.

But as I said in my earlier post has it already been done? When the motorhome was commissioned the buyer had the larger axles and air suspension and had it re plated to 4000kg to carry a motorbike/rear box

there must be a someone with a knowledge of which particular fiat engines were/are susceptible. I can't believe that the whole range is involved or it would be common knowledge and a known design fault with thousand upon thousand of victims, lets not forget that this ducato engine has been in millions of vans.

sorry for the rant
 


ian


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## 102790 (Feb 4, 2007)

*5th Gear on Fiat*

Hi Icer,

I have recently bought a second hand 1997 Eura Mobil which has a Fiat 2.5TDI engine. It is a Left hooker and the figures on the plate say 4500/5200kgs which I guess indicates that the max load is 5200kg and unlaiden is 4500kg. It is a TAG axle and has covered approx 75000 miles being recently imported from Germany by the previous owner.

I too am in a similar dilema with 5th gear. This is a big heavy vehicle and will only maintain a max of 60mph on the flat in 5th. As soon as there is any kind of gradient the speed drops and a change down to 4th is necessary. There seems to be a massive difference between the 4th and 5th gear ratios so I suspect I have the high 5th gear and could do with the lower 5th.

The 5th gear only seems to be useable between 50 and 60 mph on the flat but it will roll along on the flat at 40mph without any apparent labouring from the engine but 4th gear seems to be doing about 90% of the work unless cruising on the flat.

I would like to hear what your final outcome is as currently I am considering either the lower 5th gear modification or either re-chipping the engine but don't know enough about either to come to a decision.

Perhaps you could keep me posted.

Regards..

Ashers.


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## JockandRita (Jun 1, 2005)

Hi *Icer & Ashers*,

We have the 2.8 TDi on the 4,500 tonne Alko chassis.

It certainly doesn't like 5th at anything below 50mph (80kph), and as has been mentioned, the engine sounds ready for a change up at 45mph.

I certainly would rather take her up tp 50 in 4th and then change up, than go to the expense of having a lower ratio 5th gear fitted.

Incidently *Ashers*, the 4500kg is your maximum gross weight, (MGW), and the 5200kg, is you maximum train weight, (MTW), ie, MH + trailer. Please don't get caught unawares, for overloading. 

Jock.


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## maddie (Jan 4, 2006)

Hi I too have a fiat 2.8 td fitted with a rev counter which if it drops below 2,000 revs it labours the engine,may I respectfully sugest you listen to your engine and do not let it labour,be it in any gear and if you have to change do so.If you have a big bump on the head you cannot expect it to pull up hills etc,(wind resistance) at 70 regardless.(old van big bump strugged at 55/65 new van low profile flys at 70)Keep your engine revving sweetly and you should have no probs,it is only when stressing your engine and gearbox you will have problems.If you keep it revving freely it will return better MPG than when it is Towing/struggling.
terry


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## 102790 (Feb 4, 2007)

Hi Jock,

Thanks for the clarification on the weights.

Ours is the tag axle Alko chasis but we don't have a rev counter so rely on being mechanically sympathetic and go with the sound of the engine.

Brownhills sales rep said that the 4500 was the unladen weight and 5200 the max weight giving 700kg payload. 

Wonder sometimes if we just get told what we want to hear by these reps?

Will have to get it on weighbridge to check current weight loaded.

Cheers.

Ashers.


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## JockandRita (Jun 1, 2005)

Ashers said:


> Hi Jock,
> 
> Thanks for the clarification on the weights.
> 
> ...


Same here Ashers.

Ours too is a tag axle, hence the weights.

Bl##y Br##nhills again!!! :evil:

Loaded up for a trip away for two adults, two bikes, fuel, water and bulk gas tank full, (waste + toilet empty), we weighed in at 4370kg, leaving 130kgs spare. (we don't normally travel with a full water tank).

It's true what Maddie says about listening to the engine. Have a sympathetic ear. 

Jock.


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## teensvan (May 9, 2005)

Hi icer.

Yes i am pleased with the lower 5 the gear as we run near to 5000 keg.

We never tried a top speed run before changing the 5th gear. At 75 mph our fuel consumption was around 17mpg. At 60 mph it was around 23 mpg. Engine RPM at 60 2150 RPM.

With the lower fifth gear fitted we still get 23 mpg at 60 mph. Engine RPM is now 2650 RPM and can drive at 40mph in 5th no more revving the engine to 3100 RPM in 4 th before changing to 5 th. The engine should rev to 3800 which still gives about 78 mph top speed may be a little more.

I bought the gear cluster from fiat canterbury £151, and had the gears fitted at Gravesend transmissions. £150. www.transmissionskent.com

They gave very good and quick service.

One thing most people forget is that the fiat van was built to let white van man belt down the road at 90 mph only half loaded we run the same engine and g/box at somewhere way over 4 tonne something has to give if not used right.

hope this is of some help.

steve & ann. ----- teensvan.


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