6 months ago changed the clutch and reported here that the gearbox is showing some problems. Initially I suspected it was the input shaft bearing but now subsequently don't think this is the case.

I need a final verdict. Last week the noise started to get louder. The noise appears to disappear above 50-60mph but this is just related to the noise getting uniform the higher the speed.

It appears the noise is related to the speed of the car and not the gear. So the pitch gets higher and more uniform the higher the speed. The noise happens when both accelerating and decelerating. If I go down a hill and take the car off the gear or press the clutch then noise goes away.

So my suspicion now is that the fault must be in the final drive, the diff or the input shaft CV joints.

As most of the failure I am getting with this car are common Mk1 failure, my question to you lot is is this common failure of mk1 gearbox fault?

Very, very, hard to guess. Generally the diff makes a very characteristic noise rather like a Stuka on a bombing run.

Yes it may sound like stuka once the speed is above 50mph or at least is geting there as the noise is getting louder now. At lower speeds the sound is not uniform and is clearly noticeable now. I lifted one front wheel and turned the engine on and then put the car in gear 1,2 and third and the wheel lifted will spin happily and there is no obvious sound. Did the same test on the other wheel with the same results. The noise is clearly there on both acceleration and deceleration but only if there is load between engine and gearbox/wheels.

Went to a scrapyard to see if I can pick a box up, but they seem to be well too expensive at 175 +vat. So I left.

I understand a Mk2 box for a 1.2 8V is compatible with a Mk1 1.2 8V box. The only difference is that the front mount on the Mk2 box is different then the Mk1, but the Mk2 box still has the bolts thread for the Mk1 mount in place so it can be used. Are all the other bits compatible with the Mk1 like gear rations, speed sensor etc.?

IIRC the mk1 still has a cable speedo sensor. So you need to use that. The boxes out of every FIRE engine up to (but not including) the T Jet will fit (OK, you'll have to do a bit of boogering around, but the main castings are the same). Cinq and Sei Sporting can also be used.

Ratios seem to differ according to which size wheels are used, but I don't think anything out there will be so bad as to be useless.

IIRC the mk1 still has a cable speedo sensor. So you need to use that. The boxes out of every FIRE engine up to (but not including) the T Jet will fit (OK, you'll have to do a bit of boogering around, but the main castings are the same). Cinq and Sei Sporting can also be used.

Ratios seem to differ according to which size wheels are used, but I don't think anything out there will be so bad as to be useless.

Mk1 55,60,75, 85 and sporting will fit. The sporting (and posibly the 85) have different gear ratios for 5th. I have had 13 mk1s and have yet to find one with a cable speedo.

It does sound like the problem is diff related. When you lift one wheel off the ground the diff will turn differently as it only putting power to one wheel.

It might be worth asking around for a spares car that has other issues to get a good used box from.

Noddy said:

It does sound like the problem is diff related. When you lift one wheel off the ground the diff will turn differently as it only putting power to one wheel.

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This is why I done this test to get the diff do some work so I can listen from outside the car for unusual diff noise. Unfortunately for me this test did not reveal anything. However, the question still remains? Is the diff on punto gearbox a common failure item.

you hear that kind of noise?

well if the noises stops when crusing along dipping the clutch doesnt that point to a box problem like the input or main shaft bearings rather than the diff.

whether your coasting out of gear, in gear clutch dipped if the noise goes aways to me that suggests your diff is fine. the diff is constantly turning (well the pinion gears inside are).......

i have similar problems and had a box reconditioned - i was ripped off so ive got another second hand box that i am going to rebuild myself.

depending on how long you plan to keep yours i would junk the current box and just buy a secondhand replacement - maybe if you buy one on ebay and its rubbish or not as dexribed you can at least try and get your money back.....old boxes are a gamble plus you lose the costs of labour if youre paying a garage to fit it.....

dumbledore said:

Is the diff on punto gearbox a common failure item.

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On all the FIRE boxes if the level is allowed to get low. Ultimately the diff will try and escape through the gearbox casing, leaving a large hole.

chesh said:

you hear that kind of noise?

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Does not quite sound like that but the pitch is similar. The sound pitch in this video seems to change with the engine speed which points to the input shaft. The sound pitch on my seem to vary with car speed.

Today I done my last long trip. It does seem now a bit scary to drive as the noise is definitely stuka sound at 50-60mph. So I will have to rest the car now before I decide what to do with it after next week.

Do check the gearbag oil level.

I used to sell good Cento boxes for £50. You might try jiminwatford or Cento Painter.

Otherwise, I'd not pay £150 for one without a guarantee in writing and confirmed mileage.

Decided to do this job. Got a Mk2 box today and decided to ask around if anyone will fit for me, but could not find anybody to do it on a short notice and decided to do it myself. I just removed the old box and the new box seems to be a bit different. The speed sensor is different nut I managed to transfer it from the old one OK. However the top of the box need also transferring over. The new box does not have a reverse gear inhibitor cable and also the rod gear selector has different mounting. So is it safe to transfer the top over?

Also doing a small test on the standing gearboxes and notice when I drive the two drive-shafts on the mk1 box the noise is considerable louder then on the mk2 box. This sound like good indication the swap over will sort my problem I recon.

I also need to fill the box with oil. Any suggestion of what to use that can help the box to last a bit longer.

So is it safe to transfer the top over?

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Yes.

Best oil at a sensible price is probably the fully synthetic transmission oil FIAT sell. Failing that, ask Opie Oils.

But regular checking of the level is even more important than using a good oil.

Thanks Fingers,

Should I stear away from the cheap fully synthetic staff EuroCarParts sell?

And to add more to my verdict, Originally when I was hearing noises from my Gearbox after I changed the clutch I had some oils leaks and thought the input shaft bearing and seal may have gone. Upon inspecting the box now I have it out, it seems all fine no oil or play in the input shaft. So something else is wrong in the box. Hopefully a bad box may be also the cause of my excessive vibrations. Soon I will find out.

It'll probably be OK. (The oil, that is.) I tend to go hyper expensive for the MR2 Tub, cheap for the FIRE boxes, but level is probably the most important thing.

Finally, finished the installation.
I was hoping to use the inner CV joint in the replacement box but the joint is not the same as the Mk1. So I had to swap over all the drive shaft assembly from my car to the new box. This was ok.

Done a quick test and all seem fine. No gearbox noise anymore. However, plenty of other noises there though.

The vibration unfortunately are still there.

The other thing I noticed but cannot confirm for sure yet, is that the gear ratios are not the same as the mk1 box. I think the final drive is different.

The new box is stamped as C514.513 44, and it looks like is build sometime in 2003. My old box was build in 1998.

I think the final drive is different.

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Could be. Cars fitted with 14" wheels seem to have lower final drives than those with 13" wheels.

fingers99 said:

Could be. Cars fitted with 14" wheels seem to have lower final drives than those with 13" wheels.

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why is that? cuz of the weight of the wheels? i thought larger wheels take more power to turn but once they are in motion they need less power in maintaining same speed, wouldnt u get bigger final speed with 14 than 13 or am i perhaps mistaken

Idea is that the bigger wheels (well, actually the bigger rolling
circumference) raises the overall gearing, so that they reduce the
final drive ratio to compensate.

The clearest FIAT example is probably the Schumaker and Abarth
Seicentos (with 175/50/14 tyres as stock) have a lower final drive
than the stock 13" set up. Dafter yet, if they'd gone to 6J 14" and
fitted 195/45/14s, not only could people have bought cheaper, better
tyres, but because the rolling circumference is almost the same as the
stock 13" tyre/wheel combination, they could have kept the stock
gearing..........