Technical Fiat Bravo 1.4 T-Jet 120hp 2009 c544 m32 gearbox clunking.

[xarenwo]

Hi everyone.
I purchased a Fiat bravo 1.4 tjet 120hp back in May in Italy as a second car. It was in rough conditions, 158000km, original timing belt, thermostat open, shock absorbers original and completely blown, springs not broken but they were sitting 2cm lower than they should because the car was driven without shock absorbers for like 8 years.
Anyways, I started rebuilding it by opening the top head of the engine, changing the rocker cover seal, cleaning all the dirt due to missed oil changes or bad quality oil, inspected tappets, camshafts etc and put everything back.
Did suspension, brakes, rear bushings, basically everything on this car was done since I got it for a good price and I want a car that I can go around Europe with (like my other car) without the fear of breaking in the middle of the road.

The problem that remains and I can't seem to diagnose, is that in every gear, when you just coast, go downhill or simply use engine brake, and then you press the accelerator, there is like a backlash/knock/judder for 1 second and you can hear a knock coming from the engine bay. It's consistant, in every gear, at any speed, and it becomes less apparent with higher rpm, it's louder with lower rpm. You don't need to shock the accelerator pedal to have this, even if you press it gently it does the same.
I read on Italian forums that other people might have had this problem and it's due to the gearbox just being clunky by design, and back in the day they had it changed under warranty but the new one was the same.
Does your fiat bravo's do the same ? Even on diesel maybe ? Also, sometimes when I insert a gear, when I first release the pedal, there is a slight noise, nothing bad, it's just a noise like the gear wasn't fully engaged and it's engagign when lifting the clutch, no grinding, no bad noise, just weird compared to other cars i've driven.

I did inspect everything and including the following:
Re-did driveshaft boots, both inside and outside, checked for play and scorring on the bell of the inside tripod, there are some shiny parts but nothing you can feel by hand. If I hold steady the housing and try to make the inside tripod play, there is some slight play, but nothing bad. I did also a test where I did this at different depths inside the tripod housing, inserting the bearings deeper or less deep, and the play is exactly the same. This was in my opinion not the cause of the problem ,since when the car drives straight, the bearings always go in the same position on the housing, so if that would be the problem, when I insert the tripod bearings completely inside the case, that would make them run in a new position where it usually doesn't run, so the play should have became smaller/bigger, but it did not. The bearings themselves did not have any play in my opinion.
I changed all engine and gearbox mounts of course.
I changed the suspension arms obviously, that would be the first thing I would check too.

I did take off the gearbox and I did the rear main oil seal, flywheel and new clutch. I inspected the play in the primary shaft on my gearbox and there was no play. I also changed all oil seals, but that's irrelevant. I did notice that turning the primary gearbox shaft, there is a lot of free play (when you turn it not when you pull side to side) so I studied the gearbox, and I noticed that when the synchronizers engage, there might be around 2-3mm of free play in those tooth, and that could cause all this "delay/free play", and that would be normal and by design, not a defect, just a clunky gearbox.

The gearbox does not have any symptoms of bad bearings, no whine, no play, shifter does not move when accelerating, when I got the car I pulled out 2.3l of oil from the gearbox which means there was a total of 2.5 (200gr stays inside differential housing), that is more than what fiat recommends and that's how this gearbox should be filled in order to lubricate better the bearing near the 6th gear. I think the fact that it had more oil helped and that's why this gearbox is still ok at this mileage given all the problems that is causing on other cars since it was engineered. I put myself 2.7 oil to carry out this legacy of overfilling and hopefully helping the life of the bearings.

Symptoms did not change since after new flywheel and everything else I did (it obviously was way worse before I did the suspension parts).

I will try to find the videos and pictures and attach them, but if any of you have this "problem" you will definitely notice it because it's very annoying. You just relax and drive slowly, release the accelerator and then when you press it again the car shakes a bit and there is a clunk, it's like the flywheel would be bad, and there are no springs on the clutch disk. But the flywheel is ok, and also even if it would be bad, the symptoms between 2 different flywheels would at least change a bit.
I will try to attach the video of the gearbox "free play" to make you understand what I mean, basically when you move the primary shaft, there is a free play and delay until the differential starts moving, and if you do back-forth, you can hear kind of a "clunk" which is normal but annoying.

Here are some videos and images.
This was the old flywheel, free play is irrelevant and axial play was 1.6mm whilist the new one had 3.3mm of freeplay (barely 1 tooth) and 0.7mm axial play which is well whithing Luk's spec of 7 tooth free play and 3.5mm of axial play if I remember right.


This instead is the driveshaft on the tripod part.
The play is minimal and with the grease that play is almost entirely eliminated. The bearings do not present any axial play.


This is the video with the gearbox play I was talking about. It kind of sounds similar to the noise I get when driving, but wouldn't this mean all c544 m32 gearboxes have this ? That's why I'm asking if you ever experienced this.




I'm also attaching some pictures.

Thanks

 

[bugsymike]

I had similar noise taking up drive in a Vauxhall Combo1.3 MJ (rebadged Fiat Doblo) like you, did all the usual checks and even put it on friend's MOT pit so I could go under safely whilst another mechanic took up the drive in first and reverse with handbrake on, still nothing obvious. That one didn't have the DMF flywheel, something I am not a fan of, as feel it is another unnecessary complication.
I felt it was something to do with the driveshafts possibly , but never got to the bottom of it and it didn't get any worse so was sold on.

 

[AnthonyH]

I've read your comments and i could guess - you bought a cheap/bad clutch.

 

[xarenwo]

I've read your comments and i could guess - you bought a cheap/bad clutch.

It's original Luk. The clutch doesn't have anything to do with this, the symptoms are the same as before. Even the clutch I changed was good but the CSC was tired and making bearing noise, which is why I changed the whole clutch. Anyways, the clutch disc doesn't even have springs on it because it has DMF so there is literally nothing that could provoke this from the clutch side.

 

[AnthonyH]

Change the gearbox? I mean you can get a secondhand one in the UK for most Fiat cars at a reasonable price.

With difficult to find problems that aren't causing problems to drive, usually i just give up, and get used to it, because fault finding can feel like a never ending journey...

All of my cars are 10+ years old and all of them have 4+ jobs that I could do on them. But the law of diminishing returns kicks in. It becomes too expensive or too time consuming. It helps that I have no pride in the cars at all! They need to get me from A to B safely and economically and what they look like doesn't matter.

 

[xarenwo]

Change the gearbox? I mean you can get a secondhand one in the UK for most Fiat cars at a reasonable price.

With difficult to find problems that aren't causing problems to drive, usually i just give up, and get used to it, because fault finding can feel like a never ending journey...

All of my cars are 10+ years old and all of them have 4+ jobs that I could do on them. But the law of diminishing returns kicks in. It becomes too expensive or too time consuming. It helps that I have no pride in the cars at all! They need to get me from A to B safely and economically and what they look like doesn't matter.

I'm not in UK, where I live you can't find them as cheap.
Anyways, my gearbox is not giving any symptoms of being bad, at 162000km has no bearing issues, which means the shims behind the bearings are correct from factory and is a successful exemplary. Given this, I can always take it apart and repair it myself without the proper tool that allows you to shim the gearbox, which costs 1600 euros and would not be worth to fix 1 gearbox.
If you buy another used gearbox, it could be good, or it could be way worse, no way of knowing it, and unless you bring your car to an authorized mechanic to put the gearbox on the car with proper invoice and everything, nobody will give you any warranty in case of any problems, so you spend 6-700 euros on an used gearbox and it might be completely broken and you have no warranty.

I ordered both driveshafts new, I know it's better to repair the OEM ones, but I ordered GSP brand, and if they don't last as much as original ones I don't care, since I can always repair the original ones later with proper quality parts, but as of now, I don't have much time and it's faster for me to just replace everything.

If the problem goes away, good, the oil consumption problem I had was due to pcv valve broken tube, now it consumed around 80ml/1000km which is great, everything else on the car is new, literally, so I have a car to use for the next years.
If the problem does not go away, then obviously the only left variable is the gearbox, and at that point I will take it apart and investigate the problem and repair it, since as I said, the shims should be ok, so I can just replace the bearings and inspect the differential, since if this problem is from the gearbox, the differential is to blame, and you can buy a new differential for 250 euros or around that, not used.

I will update you all once my driveshafts arrive and I will install them.

 

[AnthonyH]

I did some digging...the symptoms you describe are gearbox bearing failure. It was a very common problem with the C544.

The same gearbox was used by GM in the Astra, Corsa, Insignia, Zafira and many others. So you can get repair parts easily.

 

[xarenwo]

I did some digging...the symptoms you describe are gearbox bearing failure. It was a very common problem with the C544.

The same gearbox was used by GM in the Astra, Corsa, Insignia, Zafira and many others. So you can get repair parts easily.

Aren't the gears different for different cars based on engine? Where did you find sources that clunking when shifting the torque from idle to acceleration or "accelerating/decelerating" is a symptom of gearbox failure ? I looked online for weeks and all I could find is that they have noise when engaging 1st and 2nd and that's pretty normal on those boxes, it's from the selector mechanism, not from the gears. And then other people forgot to tighten the bolt of the gearbox or bottom engine mount and things like that. I did not find even 1 thread that was talking about clunking without whining, jumping out of gear, not being able to select some gears or shifter lever movement in 1st and 5th gear (or 6th when bad). Everyone says the gearbox starts with noises, then when it gets bad the shifter will move and then it's already a bit too late to start fixing it because the shafts are already moving towards each other so the gears will get messed up. There is no other symptom with my gearbox, everything works perfectly other than this clunk. All gears work on cold or hot engine, no vibration, no noise, no whining, no movement in the gear lever at all.

 

[AnthonyH]

The M32 is notorious for problems, in particular bearings. You were probably searching for the Bravo gearbox, if you search for M32 it brings back a terrible gearbox plagued with issues.

I realise you don't think it's the bearings, but you said this;

"The problem that remains and I can't seem to diagnose, is that in every gear, when you just coast, go downhill or simply use engine brake, and then you press the accelerator, there is like a backlash/knock/judder for 1 second and you can hear a knock coming from the engine bay. It's consistant, in every gear, at any speed, and it becomes less apparent with higher rpm"

This is bearings as far as I know.

 

[xarenwo]

The M32 is notorious for problems, in particular bearings. You were probably searching for the Bravo gearbox, if you search for M32 it brings back a terrible gearbox plagued with issues.

View attachment 475170

View attachment 475171

View attachment 475172

I realise you don't think it's the bearings, but you said this;

"The problem that remains and I can't seem to diagnose, is that in every gear, when you just coast, go downhill or simply use engine brake, and then you press the accelerator, there is like a backlash/knock/judder for 1 second and you can hear a knock coming from the engine bay. It's consistant, in every gear, at any speed, and it becomes less apparent with higher rpm"

This is bearings as far as I know.

I'm sorry but I have to disagree for now , this because you sent me the exact same thing that I said on top about the problems. Play of the shifter knob in 1st 5th and 6th, hard to select gears and bearing whining. It's becoming loud when driving after 40mph and so on. I read that pdf from eco-torque company too months ago, they are refurbishing the m32 gearboxes.
I read and watched many videos about the m32 gearbox and I know it's been on lots of cars and it's mostly problematic ok the astra vxr. I repeat, I have none of those problems you just mentioned, I just have a knock like the bushing of the suspension arm would be bad. If that would come from the differential it would disintegrate, it's loud and you can feel it, there would be other symptoms for sure, bearings don't cause loud clunk noise for 1 second and then nothing else, that's what I'm trying to explain. Once I eliminate the driveshaft variable I will be able to diagnose better . Did you have the fiat bravo with this gearbox and had the same symptoms and were diagnosed with gearbox failure? Because on Italian forum many people said in the beginning they changed gearbox in warranty and nothing changed, the gearbox is just loud in general when selecting 1st and 2nd and mostly because of the selection mechanism, also the successor c635 and even on alfa Giulietta Is a bit loud, but not loud as in bearing noise, just loud when operating and changing gears. But I did not find yet nothing about my problem anywhere.

 

[AnthonyH]

Fair enough. Keep us informed on how you get along.

 

[electric73]

Hi. If you have multiecuscan, could you please share what software version of the ecu you got? Here's mine

 

[xarenwo]

Hi. If you have multiecuscan, could you please share what software version of the ecu you got? Here's mine

Hi, my software version is 0022 programmed in 06/03/2009, car was manufactured in july 2009 and registered in august 2009. Why do you ask ?

 

[electric73]

Hi, my software version is 0022 programmed in 06/03/2009, car was manufactured in july 2009 and registered in august 2009. Why do you ask ?

Because according to AI, there are two software versions on bravo - mine and 1037392100. And in the second one cold start is fixed

 

[xarenwo]

As an update for everyone, I decided to rebuild the driveshafts, and the clunking and movement when releasing/accelerating is gone. I mean, there is a tiny bit from the differential when you try to move by hand, but that's perfectly normal, and it can't be felt while driving.
The problem is that the aftermarket inner axle that goes in the gearbox is not like the original design, and there is vibration now when accelerating hard from 100 to 110kmh after 4000rpm, so it's clearly some imbalance/resonance. So I have to now re-do the axles. For the right side i decided to go with aftermarket one, for the left i'm trying to find original design of the inner axle and rebuild the rest. The cv-joints at wheel side even if low quality are good for now. Unfortunately it's hard to find quality outer/inner cv joints and they will never be as good as original ones.
You can see in the second video how the tripod bearing has too much play in that cup.
The aftermarket one from GSP has different bearing design, and different cup design, you can't find the boot in the market, so if it breaks, you need to replace everything again, which is why I'm trying to find a cup that has same design. I found one from a company called FrankBerg, seems low quality bearing but I don't care about that, tripod bearings can be found, the cup itself it's impossible to find. The aftermarket ones have same design as fiat 1.3 multijet where tripod bearing only rotates and goes up-down by 3-4mm, but does not go diagonally. The ones from Bravo also rotate diagonally.
Attaching pictures to see the difference.

This is how most aftermarket cups are, the bearing has rollers as you can see, and they can only rotate, and go in-wards/out-wards. The boot design on the cup is different, as there are no straight edges, it's round everywhere, meanwhile the original design it's straight on the most outward part (Top part in the picture). So you cannot find the boot anywhere and it will not last a long time. To get decent boots you need to purchase GKN/SPIDAN/LOBRO which is original on the car, and one of the best brands for any car when dealing with axles.

Now the original design is like this .

As you can see, the bearings also rotate on their own axle, and the cup design, on the part towards us in the picture, is straight, not curved, and you can use original boots.

My plan now is to use a better quality brand of bearing, with a SKF/ GKN boot and the cup in the picture, which is from a low-quality aftermarket brand, according to the internet, but it provides the original design.
Who knows, maybe the problem with my car was just the bearing, and the cup itself is fine, even if a bit scuffed on the inside.
I will obviously test both the old original cup with the new bearing and the new cup with the new bearing to see the difference in play.
If there is no difference in play, I will try the original fiat cup with a new bearing and see if that keeps the clunking/free-play problem and the vibration due to resonance away, which have appeared with the other bearing design in the newly rebuilt axles.

For people that ask me: why don't you just buy rebuilt aftermarket axles ?
Because there are only a few, and most of them are completely different designs from the original, with impossible to find replacement boots, which will last 1 year if you are lucky, plus the outside CV-joint has a thinner snap ring, and you risk that the CV joint snaps out and you remain in the middle of the road.
It's better to reuse the original snap ring on the outer CV joint. I used original GKN/SPIDAN/LOBRO from a kit I had, which is exactly as original. On the factory CV joints from 2009, there was GKN written on them.
Besides this, as you can see from the above pics, there is a tripod bearing on the original design for the inner CV joints.
Most aftermarket solutions don't have that; they have the same design as the outside CV joint. Attaching a picture.

This is the design of most aftermarket solutions, which is the same design as an outer CV joint.
Now, for the right hand side, the longer one, I decided to go ahead and purchase one of those full axles for under 100 euros, if they last me a year, I'm good, I just want to use the car for now and be sure the problem of clunking/free play when changing gears/releasing accelerator is not from the gearbox (which is confirmed). Then I can think of other solutions, if I can repair the left one with the cheap aftermarket original cup, I will do the same for the right hand side. I will buy original GKN outer cv joint for 50-70 euros each, and then for the inside I will use the cheap cup with decent bearing and good boots from GKN/LOBRO/SPIDAN.

Besides this, now I have another problem that I've had for a while, since I changed the clutch and took off the gearbox ( or maybe before too, just didn't notice, had the car for 4 months only ). The gear lever inside the car is very hard to move, almost blocked, when the engine is cold and after sitting for a while. There is no pattern when this happens; it happened with 30 degrees Celsius outside after sitting for 2 hours, then the next day was perfectly fine after sitting for 24 hours. Now it's 0 degrees Celsius, and it didn't happen for 1 week, then suddenly again.
It's not the bowden cables for sure, I disconnected them when I felt that the lever was stiff, and I tried to move up/down from the gear selector on the gearbox, it was completely blocked. After I moved it up and down 3/4 times, it became free, and the car was working perfectly, gear changes were very smooth, and so on.
For anyone trying to tell me "it's the bearings, classic symptom of m32 gearbox failure". I re-did the driveshafts on purpose to understand if the problem with clunking/shock when accelerating-releasing the accelerator was from the gearbox or driveshafts. The Gearbox is perfectly fine, oil was changed 3 times in the past 3 months, the gears engage perfectly, and there is no noise or bearing failure symptom at all. This has something to do with the selector mechanism on top, there should be a spring and some grease, I greased it and it was better for a few days, seems like some dirt might have gone in or I don't know, after re-doing the axles again I will concentrate on this again. For now, when the selector is stiff, I move the selector up/down by hand on the gearbox to avoid putting tension on the bowden cables, then the car works like new. I'm opening a new thread on this problem.

 

[xarenwo]

Update: I purchased Pascal Tripod bearings and new OEN remanufactured outer CV joints. I disassembled them and checked for defects under the microscope, and they looked perfect, no usage, so original fiat remanufactured. For the inner joints, I found one OEM old-stock unit for the left and reused the original one for the right. The shaking disappeared, no clunking anymore either. The funny part is that the play of the tripod bearing in the cup that goes in the gearbox is the same with the new bearing and the new OEM tripod cup as it was with the old bearing and the old cup. So in the end, the problem might have been from the outside CV joints, which is weird, because they usually don't cause play; they make noise when you steer because the channels where those balls move into get pitted with time, and when the balls go from top to bottom, they make that noise.

Anyways, the car has a bit of play at the differential, like any vehicle, but you don't notice it while driving, so the problem isn't from the gearbox.

I fixed the problem with the stiff gear lever by spraying WD40, lots of it, to get any dirt out, and I did not add any grease, because grease gets stiff when it's cold and might trap more dirt in there. For now, after 10 days of daily driving, the gear lever is perfect, and the gear changes are like in a new car.