Potential leak between clutch bell housing and gearbox

[bayzoo]

I’m doing a clutch change job on my Kia Picanto 2009 1L. Before I removed the gearbox and drained the gear oil I noticed some staining between where the clutch bell housing joins onto the gearbox.

I thought I could just separate the two, clean off old gasket and apply new but I don’t want to separate them if a whole load of bits fall out!

It doesn’t seem to be a big leak if at all and it’s not worth spending the money taking it to a pro. I’m doing this clutch job as I’m using this car (which I got for free) to learn DIY mechanics. So I might just leave it!

[TwinKam]

Don't do it! Most gearboxes dismantle from the outer end.

[E-bmw]

Can you take a pic, as between the clutch bell-housing & gearbox there shouldn't be a gasket as that is not a joint I would expect to have fluid behind it, most gearboxes are sealed & the bell-housing is just a shaped bit of metal. Any fluid in there would be immersing the clutch plates & fly-wheel.

Edited by E-bmw on Monday 30th March 09:22

[bayzoo]

E-bmw said:

Can you take a pic, as between the clutch bell-housing & gearbox there shouldn't be a gasket as that is not a joint I would expect to have fluid behind it, most gearboxes are sealed & the bell-housing is just a shaped bit of metal. Any fluid in there would be immersing the clutch plates & fly-wheel.

Edited by E-bmw on Monday 30th March 09:22

Thanks

It definitely comes in 2 sections:

Edited by bayzoo on Monday 30th March 10:00

[TwinKam]

FWD cars don't have a separate 'bell-housing', it's just part of the main casting.
A leak from that mid casing joint will not get anywhere near the clutch.
The gasket will almost certainly be a 'liquid' type.
To re-seal it will, as I suggested, reguire a strip-down of the box, and yes, bits will 'fall out'.
It's not a job to be undertaken lightly, it's a specialist job, even most garages don't repair gearboxes. But if you can get hold of a manual, and you don't mind the car being off the road for a while, it'd be a good learning experience for you. But you may see things that you wish you hadn't...

[bayzoo]

Thanks for this - I need the car back on the road soon so I’ll skip this one. I’m glad I asked - I would definitely barely love to do this sort of job on a proper project car in the future.

[E-bmw]

bayzoo said:

E-bmw said:

Can you take a pic, as between the clutch bell-housing & gearbox there shouldn't be a gasket as that is not a joint I would expect to have fluid behind it, most gearboxes are sealed & the bell-housing is just a shaped bit of metal. Any fluid in there would be immersing the clutch plates & fly-wheel.

Edited by E-bmw on Monday 30th March 09:22

Thanks

It definitely comes in 2 sections:

You miss my point, I am not saying it doesn't come in 2 sections, I even showed pics (random car) showing the gearbox in 2 sections but you are saying there is a leak coming from the "gearbox/bell-housing joint". In the great majority of cars that is just a plain joint of 2 bits of metal that are bolted together.

Without seeing your actual leak I am not sure where it is coming from but (unless your bell-housing is 1/2 full of oil from either the engine or the gearbox main seal) it will NOT be coming from where you say.

Typically the situation will be:

Engine (obviously oil-filled) output shaft comes out with an oil seal round it, this could leak oil into the bell-housing, which will normally have a tell-tale hole to see this.

Bell housing with no gasket to engine end.

Bell housing with no gasket to gearbox end.

Gearbox with an oil seal round the input shaft, this could leak oil into the bell-housing, which will normally have a tell-tale hole to see this, the same hole as above.

Typically you will then have a split in the middle of the gearbox or at the other end to allow the gears to be fitted.

See the pics I posted for examples of bell-housing & gearbox.

If you also look at your middle pic, that is the inside of the bell-housing, and you can see there is no oil-bath in there that could leak out, so there are no gaskets, just a tell-tale hole to show you have an internal leak, but that is always (AFAIK) at the engine end not the bell-housing to gearbox end, as you say.

The tell-tale hole can be seen at the bottom of my bell-housing pic.

Edited by E-bmw on Monday 30th March 12:17

[bayzoo]

said:

Ok thanks I’ve got it now. I’m getting my terminology mixed up - learning as I go here.

There is a chance the staining could be engine oil as the sump was leaking but looked too far away for that to be the source.

I don’t have any pics of the area I thought was leaking unfortunately.

[E-bmw]

bayzoo said:

Ok thanks I ve got it now. I m getting my terminology mixed up - learning as I go here.

There is a chance the staining could be engine oil as the sump was leaking but looked too far away for that to be the source.

I don t have any pics of the area I thought was leaking unfortunately.

No problem, just don't want to give you incorrect advice, every day is a school day.

Ref. Sump leak, you would be surprised how far oil will spread under an engine due to the wind passing underneath.

Unless there is an obvious point of leak, the best thing to do is to forensically clean the whole area, then run the engine for a bit see if anything appears, go for a short drive, see if anything appears, leave it overnight, see if anything appears and so on, progressively doing more and checking regularly if there are an signs.

Unfortunately, it can sometimes take a while to find the actual cause, and then, and only then is when you look at fixing it.

[TwinKam]

Forget the pics of the inline RWD gearbox & separate bellhousing in E-bmw's post, they're irrelevant and confusing in this thread about a transverse FWD 'box.
FWD 'boxes have the 'bellhousing cast as-one with the first part of the gear casing. There is then a second-casing (housing the main gear clusters & selector forks etc), and usually a third end-casing (sometimes housing 5th or 6th speed). Call the casings 1, 2, & 3. This Picanto doesn't have a separate '3'; the end cover is cast as-one with '2', as clearly shown in the exploded diagram: 43115 is '1' and '43111' is '2'.
So there is only one joint, that one between 1 & 2, where OP originally thought it was weeping from (and I can see that that has a liquid gasket, 43116C). A leak from that will be obvious if cleaned off and monitored.
There is an oil seal for the input shaft (43143). If it leaks, oil may dribble out at the lowest part of the bellhousing.
There are two oil seals for the output shafts (43113 & 43119). Any leak from those will be obvious.
There could also be weeps from the gearchange shaft, or the breather.
I very much doubt that a sump pan oil leak would travel laterally, forwards and around the wider than itself bellhousing part and find itself at the aforementioned joint. Maybe on a RWD car with an inline gearbox, but not on your transverse one.
TLDR, just wash it off and keep an eye on it for now.

Edited by TwinKam on Monday 30th March 15:12

[E-bmw]

TK.

Fair comment, I was over-simplifying and thinking mainly of RWD, many FWD are as you say.

That still ratifies the comment from both mine & also your post that a pic is needed to help further, but clean/monitor is the way forward for now.

[bayzoo]

E-bmw said:

bayzoo said:

Ok thanks I ve got it now. I m getting my terminology mixed up - learning as I go here.

There is a chance the staining could be engine oil as the sump was leaking but looked too far away for that to be the source.

I don t have any pics of the area I thought was leaking unfortunately.

No problem, just don't want to give you incorrect advice, every day is a school day.

Ref. Sump leak, you would be surprised how far oil will spread under an engine due to the wind passing underneath.

Unless there is an obvious point of leak, the best thing to do is to forensically clean the whole area, then run the engine for a bit see if anything appears, go for a short drive, see if anything appears, leave it overnight, see if anything appears and so on, progressively doing more and checking regularly if there are an signs.

Unfortunately, it can sometimes take a while to find the actual cause, and then, and only then is when you look at fixing it.

Thanks - no worries, yes this clutch change job has grown arms and legs! But good learning assuming I can get it all back together and working.

[bayzoo]

TwinKam said:

Forget the pics of the inline RWD gearbox & separate bellhousing in E-bmw's post, they're irrelevant and confusing in this thread about a transverse FWD 'box.
FWD 'boxes have the 'bellhousing cast as-one with the first part of the gear casing. There is then a second-casing (housing the main gear clusters & selector forks etc), and usually a third end-casing (sometimes housing 5th or 6th speed). Call the casings 1, 2, & 3. This Picanto doesn't have a separate '3'; the end cover is cast as-one with '2', as clearly shown in the exploded diagram: 43115 is '1' and '43111' is '2'.
So there is only one joint, that one between 1 & 2, where OP originally thought it was weeping from (and I can see that that has a liquid gasket, 43116C). A leak from that will be obvious if cleaned off and monitored.
There is an oil seal for the input shaft (43143). If it leaks, oil may dribble out at the lowest part of the bellhousing.
There are two oil seals for the output shafts (43113 & 43119). Any leak from those will be obvious.
There could also be weeps from the gearchange shaft, or the breather.
I very much doubt that a sump pan oil leak would travel laterally, forwards and around the wider than itself bellhousing part and find itself at the aforementioned joint. Maybe on a RWD car with an inline gearbox, but not on your transverse one.
TLDR, just wash it off and keep an eye on it for now.

Edited by TwinKam on Monday 30th March 15:12

Thanks for explanation. The reason I suspected a leak from the gearbox was the patch of fresh looking oil right in between the join (I had cleaned this a few weeks before), and the fact that when I drained out the old oil the level was quite low (though I think the oil had been in there since 2009).

I need to have the car back on the road by the 24th April so thought I’d investigate this whilst I have it all apart for the clutch.

Last thing I want is the stress of separating the joint, and bunch of bits fall out! I can find a workshop manual that goes through a gearbox rebuild. This is a job I’d love to try but not under pressure.

There is a garage near me (I’m in Derry, NI) that does gearboxes so I might chat to them but I’ve already spent a fair bit of cash on parts on this cheap wee car it’s becoming a sore point. Though you can’t put a price on education…

[E-bmw]

bayzoo said:

E-bmw said:

bayzoo said:

Ok thanks I ve got it now. I m getting my terminology mixed up - learning as I go here.

There is a chance the staining could be engine oil as the sump was leaking but looked too far away for that to be the source.

I don t have any pics of the area I thought was leaking unfortunately.

No problem, just don't want to give you incorrect advice, every day is a school day.

Ref. Sump leak, you would be surprised how far oil will spread under an engine due to the wind passing underneath.

Unless there is an obvious point of leak, the best thing to do is to forensically clean the whole area, then run the engine for a bit see if anything appears, go for a short drive, see if anything appears, leave it overnight, see if anything appears and so on, progressively doing more and checking regularly if there are an signs.

Unfortunately, it can sometimes take a while to find the actual cause, and then, and only then is when you look at fixing it.

Thanks - no worries, yes this clutch change job has grown arms and legs! But good learning assuming I can get it all back together and working.

I didn't realise you already had it apart & the pics were of your gearbox.

That pic shows the gearbox end of the bell-housing to be dry, but there does seem to be some "wetness" in the clutch debris, if there is (you will be able to tell better as the pic doesn't fully show the bottom) then it is likely from the engine main seal.

If so you will likely have found the flywheel damp with oil.

This is a definite "do while you are there" job.

[bayzoo]

E-bmw said:

I didn't realise you already had it apart & the pics were of your gearbox.

That pic shows the gearbox end of the bell-housing to be dry, but there does seem to be some "wetness" in the clutch debris, if there is (you will be able to tell better as the pic doesn't fully show the bottom) then it is likely from the engine main seal.

If so you will likely have found the flywheel damp with oil.

This is a definite "do while you are there" job.

Thanks, yes apologies I didn’t make that clear - there wasn’t any wetness around the clutch debris or release bearing, but the rear main seal was a little wet behind the flywheel and I’ve since replaced this with a genuine Kia seal.

So my options for the potential ‘mid casing’ leak are:
- leave it and hope it was just related to the engine oil leak
- open it myself to clean and reapply the liquid gasket, but risk having bits fall out
- take it to a gearbox specialist but costing me £££

I love a project and learning, but time is against me and I don’t need the stress - this is a car I’ll run for 2 or 3 years hopefully.

[E-bmw]

bayzoo said:

E-bmw said:

I didn't realise you already had it apart & the pics were of your gearbox.

That pic shows the gearbox end of the bell-housing to be dry, but there does seem to be some "wetness" in the clutch debris, if there is (you will be able to tell better as the pic doesn't fully show the bottom) then it is likely from the engine main seal.

If so you will likely have found the flywheel damp with oil.

This is a definite "do while you are there" job.

Thanks, yes apologies I didn t make that clear - there wasn t any wetness around the clutch debris or release bearing, but the rear main seal was a little wet behind the flywheel and I ve since replaced this with a genuine Kia seal.

So my options for the potential mid casing leak are:
- leave it and hope it was just related to the engine oil leak
- open it myself to clean and reapply the liquid gasket, but risk having bits fall out
- take it to a gearbox specialist but costing me £££

I love a project and learning, but time is against me and I don t need the stress - this is a car I ll run for 2 or 3 years hopefully.

Do you have a bigger pic showing the oil on the gearbox housing?

I ask because it may help to see where it is in relation to the bell-housing tell-tale hole.

I am guessing that the "sensor" shown unplugged in your pic is the reversing switch, if so, that will likely have an o-ring on it & if it is "oil-immersed" that could also be the source of the leak.

[bayzoo]

Thanks - I’ll get a picture tomorrow evening as I’m in Scotland just now and I’ll point out exactly where the staining was.