Technical 4x4 Gearbox Noise

[doctorchris]

I've posted about this noise a couple of years ago but nobody recognised the symptom. Then the noise went away. Now, after a long drive down to London and back via various other places, the noise is back.
It is halfway between a grinding noise and a rattle. It comes from the front of the car and occurs when the accelerator is pressed in higher gears, eg 4th and 5th, at realtively low road speeds, though not at low enough speeds to be putting a strain on things.
It does not appear to be exhaust noise. I feel it comes from the gearbox. As the car has 4 wheel drive I cannot jack up the driven wheels only to get underneath and trace the noise, I'd have to jack up all 4 wheels and that's just too dangerous. I could ask the dealer's service dept to trace the noise but the car is out of warranty and as I don't think the noise is terminal I don't want to get into paying for diagnosis and repair.
Just curious as to whether anyoe else has had this noise and, if so, if a diagnosis has been made.

 

[HP]

Little help maybe, but I'd be looking to check the gearbox oil levels.

 

[doctorchris]

A sensible suggestion and I will do so, however there is no evidence of a leak so I suspect a lack of gear oil is not the cause.

 

[Herts Hillhopper]

I too get the noise you describe from somewhere in my 4x4's drivetrain at low speeds in higher gears. I feel it emanates from the transfer gears that connect the front diff to the rear-drive prop shaft. Although I suppose it could be something shaking against the 4x4's undertray? Its done it on and off over the past 22k miles and doesn't seem any better or worse during that time.
I've never really worried about it: 2 solutions that make it stop -- changing gear, or backing off the gas.

 

[doctorchris]

Thanks HH, now I know it's probably a characteristic not a fault I feel better.
When I get to test drive the Panda Cross I'll wind the window down and listen for the noise on that as well.

 

[doctorchris]

When I finally got round to checking the gearbox oil level on my Panda I found it needed topping up with about 200ml of oil, this represents about 7.5% of the total capacity. Thanks are due to HP and have been sent. I don't understand where the oil has gone as there are no leaks, although there is a breather on top of the box which was a bit greasy, maybe there is some loss from there. The loss may even be due to evaporation as the 4x4 uses a fairly thin gear oil. Maybe the factory never filled the box correctly. Who knows?
Anyhow, the noise is still there but the gearchange is smoother. I used to be experience a crunch changing up from 3rd to 4th and this has disappeared. So some benefits from topping up the gearbox.

 

[Jai]

which grade oil was it in the end?

 

[doctorchris]

Panda 4x4 gear/transaxle oil is SAE 75W-85 fully synthetic. Castrol SMX-S fits this spec.
Note that the 4x4 is the only Panda to use this grade of oil in its gearbox as far as I know, though I don't know about the 100HP.

 

[HP]

For the 100hp the manual says Tutela Car Technyx, which after a bit of digging is a 75w/85 the same as the 4x4

Cheers for the reference with SMX-S, I know where I can get my hands on that!

 

[Herts Hillhopper]

Finally got round to checking the gearbox oil in the Hillhopping 4x4, and was surprised that it took 300ml or so to bring the level up! Now much quieter, and possibly easier to engage gears too.

This leads to a couple of questions: where did the oil go (as above, no obvious leaks, although signs of a fine 'mist' of oil on top of gearbox housing from breather), and secondly, how many other 4x4 Pandas are running around with low gearbox oil? The first service check of gearbox oil level isn't until 80,000km according to the instruction manual.

How to you check - like this! Bit tricky to get to:

• Car must be on level ground, or with all 4 wheels lifted equally if you're lucky enough to have access to a lift (I don't!)
• Remove the 4x4 undertray (put a trolley jack under that to hold it up as you unbolt it, as its surprisingly heavy)
• Wear gloves as gear oil is not good for the skin and smells horrible
• Clean around the fill/level plug to prevent dirt getting into gearbox
• Remove fill/level plug. Its a 12mm Allen hexagon, but very tight and fitted with thread seal compound. You'll need a 12mm hex bit on a socket wrench to undo it (its about 1/3rd way up gearbox on the front towards the 'bell' shaped clutch housing, near a coil of black plastic piping)
• Fill with oil (as above, Castol SMX-S or other fully synth 75W-85 gear oil for the 4x4) until it runs from the filler (ie so the oil level is level with the bottom of the filler hole). Gear oil bottles can be used with the spout pointing upwards - just squeeze to get the oil out.
• Refit in reverse order. (I didn't reapply thread seal, but probably should have done). The plug is slightly tapered so it tightens to form a good seal. Again, clean the plug before refitting it.
• Test drive and hear the difference!

Pete

Thanks to DoctorChris and HP for drawing attention to this

 

[shaddowdragon]

Most likely the Prop Shaft. Have just come from the dealership and it is not good news. Anyway, there are suggestions on other forum topics. Look for this forum topic


panda-classic/64735-4x4-drive-shaft-making-damn-noise

 

[doctorchris]

I'm reviving this thread, with reference to my Panda Cross.
Now that it has clocked up just over 12,000 miles, rapid gear-changing from 1st to 2nd produces a slight crunch. My 4x4 Climbing did this as well, after a while, though not sure after how many miles.
I have not noticed the other gearbox noises described in this thread, though the noisier Diesel engine may be masking them.
I've just checked the gearbox oil level today and it is correct.

This phenomenon does not worry me, I feel it is a characteristic rather than a fault, and I just need to take this gearchange a bit slower.
Interested, though, as to whether other 4x4 owners have noticed this happening.

 

[panda4x4x4x4]

mine is ok at 22000 miles

 

[patroclueus]

mine crunches in most gears

40,000 miles 1.2 Climbing

going to check the gearbox oil and replace and see if that cures it... will report back

 

[Herts Hillhopper]

Mine has a tendency to crunch when going down the box into third in a hurry. It doesn't do it if you push the lever more slowly so suspect the synchromesh is a bit weak.

However, I ought to recheck that gearbox oil level too, as now at 73k miles (suspect was about 35-40k when I mentioned this back in this thread a couple of years back) - not sure if that would make any difference though.

P

 

[Advanced Driver]

mine crunches in most gears

My 100HP has done this since new, but it's intermittent. It's generally a very notchy gearchange. Even when I change slowly I still get problems. Although the 100HP has a 6 speed gearbox I believe they are pretty much the same as the 5 speed ones.

 

[trackdayqueen]

Mine has a tendency to crunch when going down the box into third in a hurry. It doesn't do it if you push the lever more slowly so suspect the synchromesh is a bit weak.

However, I ought to recheck that gearbox oil level too, as now at 73k miles (suspect was about 35-40k when I mentioned this back in this thread a couple of years back) - not sure if that would make any difference though.

P

Yep, likely the syncro on third is on it's way out.

 

[4x4]

Hi Guys,
This reply is about the 'gearbox' noise not about the crunching.
I have a 20 month old MJ Cross that developed a rattle at between 1,600 and 2,000 rpm that was getting louder as the milage increased (now a massive 12,000miles!). It was especially loud in 3rd and 4th although present in 2nd if going steadily up a slope at 1,800rpm. Most noticeable if you had the windows down in a walled area i.e. the sound bounced off the walls and could be easily heard. With the windows up, the rattle sort of came up from in between the front footwells i.e. gearbox. Most annoying.

Well, it's the transfer box and Fiat have a fix for it.

The problem lies between the transfer box and the propshaft. The Fiat fix is to shim out the play either in the box or between the box and shaft.
I don't know how or where the shims fit but I can say there were a lot of oily finger prints all over the front of the front propshaft and the coupling on the rear of the transfer box.
The fix has reduced the rattle by 75% and the Fiat garage in Nicosia (Cyprus) will have it in again to shim some more. They were concerned about removing all the play just in case something broke. However, they will now shim it further (i.e. follow Fiats instructions) which I hope will be rid of the rattle for good.

That and the knocking from the rear callipers has spoilt my enjoyment of the car to date but I can tell you this, it's bloody good off road on gravel, rock, dirt, sand and hasn't got bogged down or stuck yet. It's also quite good in shallow streams but does cause the heart to miss a beat when is slips about whilst the EDL works out what to do. Take away the knocks and rattles and it's a super little truck.
Have fun!