Technical Uno Fire 1100 - Transmission selector oil leak.

[DigitalNomad]

Hi folks,

Just gone through my to-do list of my little Uno and need a little advice with repairing a oil leak.

I actually noticed the leak a couple of months ago, but it just made a small drop now and then so I was not to concerned at the time. It has gotten worse now and every morning or wherever I park there is always a small amount of oil on the floor.

I traced the leak to the back of the selector on top of the transmission. There is a what seems like a long pin that enters the selector. To this pin on the outside is connected some other leavers/arms from the gear leaver assembly. Here in South Africa, the particular transmission is known as the “Fish Tin” model, a nick name it allegedly got because of the golden colour of the selector cover. I had the selector cover removed and resealed about two months ago in a process of elimination but soon afterwards I got in under the car myself to find the fault. I cleaned the transmission properly all-round with engine cleaner and left it standing a couple of hours and found the trickle quit fast.

My question is simple really. Is there some kind of o-ring type of seal in there that I can replace myself, or does the whole transmission have to come out etc. With the help of a couple of great and very helpful forum members and some luck, I just got my car sorted out myself after being ripped of badly by so called professional mechanics and auto electricians, I really do not feel like starting all over again.

If anyone has had experience with this particular type of leak, please help. The car is a 1994 Uno Fire 1100, the leak is not a constant dripping of oil because when I am parked, the transmission oil accumulates at the bottom of the transmission I suppose and the leak is above this level right at the top. I am suspecting that when I drive, oil is obviously splashed all over the place inside of the transmission even into the selector area where a tiny amount escapes via a possible broken seal which could of worn out because of all the years of use each time the gears are changed. Car has 180,000km on the clock. When I am parked, instead of the droplets just blowing away in the wind while driving, the last bit that was at this leak area, slowly trickles down the outside of the transmission and onto the ground. After a couple of hours, it stops only to happen again next time I drive.

Warm regards,

 

[rawill]

I am a bit unclear about where the leak is coming from. On my Unos there is a little tin cover the comes off the top of the box. If the leak is coming from there that will be an easy fix. I think there is a gasket there. But to be sure a pic would help. I have had mine off to check the top of the selectors.

Is it this cover

The pin doesn't go through the tin cover, but taking off the tin cover gives access to the selector rod. That was real helpful for me as someone had been in there before and taken it apart. They left the central collar out so I had an absolutely hopeless gear shift mechanism that would not sit in the 3-4 gate. I pinched a collar from my donor car and it was all good. But you didn't want to know all that did you!! It was all thanks to alexGS that I found the problem.

 

[jjhepburn]

If there is an oil leak from all the way up there then I am guessing there must be too much oil in the gearbox, the oil level should only go about half way up. You will see two fill plugs, one right at the bottom (used for draining the gearbox) and one about half way up on the front. This one is used for filling, you poor oil in until it starts coming out of this hole (with the car on level ground).

But as for o-rings there are two so I guess you could replace those, you will need to undo the nut at the end then you can slide out the selector shaft where the o-rings are. Be careful though as there are many springs and leavers in that area that need to go back together in a specific order.

 

[DigitalNomad]

I am a bit unclear about where the leak is coming from. On my Unos there is a little tin cover the comes off the top of the box. If the leak is coming from there that will be an easy fix. I think there is a gasket there. But to be sure a pic would help. I have had mine off to check the top of the selectors.

Is it this cover....

Hey there,

Thankyou for your reply. Yes, my cover looks exactly like that one, it is goldish in color too. I have had the cover's gasket replaced and sealed etc. It is definately leaking from the back where the pin enters just below where the cover fits on. In the front (on your photo) you will notice a nut which I am suspecting is holding that pin in place. I am suspecting that at the back side where it turns, there would be some sort of o-ring that has gotten worn out.

Warm regards,

 

[DigitalNomad]

If there is an oil leak from all the way up there then I am guessing there must be too much oil in the gearbox, the oil level should only go about half way up. You will see two fill plugs, one right at the bottom (used for draining the gearbox) and one about half way up on the front. This one is used for filling, you poor oil in until it starts coming out of this hole (with the car on level ground).

But as for o-rings there are two so I guess you could replace those, you will need to undo the nut at the end then you can slide out the selector shaft where the o-rings are. Be careful though as there are many springs and leavers in that area that need to go back together in a specific order.

Hi there,

Thanks for the reply. When the car is standing level, and the transmission is filled properly, I can put my little finger in the filling hole and just slightly feel the oil level - so I am sure it is not over filled. I am suspecting that when driving etc. oil is splashed inside the transmission all over the place, and because I have a broken seal at the selector, when I have stopped, that bit of oil that has accumelated there during driving leaks out untill it is done and then stops untill I go driving again.

I can easily take of the cover and reseal it again, haven't done it yet though. Would I need special tools to get that pin out and replace the o-ring at the back. Is there a o-ring at the back side - I am suspecting so. I am pretty mechanical minded, but not a pro by far, do you reckon this is a difficult thing to fix? The o-rings, are they special Fiat stuff or will any simmilar size o-ring do?

Warm regards,

 

[rawill]

I suspect you are right. You can take the cover off. That will expose the selectors from above. I imagine you can take the shaft out, I have never done it. I only took off the nut you can see and slid the shaft out towards the bulkhead enough so I could slip in the 'missing' collar on the selector shaft. I do not know what would happen if you took the shaft right out. I hope JJhepburn or alexGS will come on and give some guidance. I have never had an Uno gearbox fully apart.

 

[alexGS]

Well, sadly I don't know whether there are O-rings or whether the shaft comes right out, and I don't have a gearbox handy to check. But fortunately, jjhepburn does and has already described the O-rings in post 2172138, four messages ago.

It sounds a good plan to undo the nut at the front end and slide the shaft out. I'm sure a generic O-ring would do the job. Perhaps something about the size of a garden tap O-ring?

Like jjhepburn, I'm a little surprised that the leak is significant enough to notice, I think I would suspect the tin cover gasket first. I have to admit I wondered if it was engine oil leaking from the distributor and running around the gearbox casing, but obviously not.

So, sorry I'm not much help!

-Alex

 

[DigitalNomad]

Thank you guys. I will open up the cover the moment the rain clears up and take a look and keep you posted.

I also initially suspected regular engine oil, but nope, it is all nice and dry and the oil that is leaking is almost clear, not black like the oil I see on the dipstick. A little bit accumelates next to where the speedo cable screws in, so I also thought that perhaps it was escaping from there, but nope, it was higher up.

If I put my finger behind the cover just underneath the entrypoint of the rod, I get almost clear oil on my finger.

I will first just open it up and eyeball it good before doing anything.

Thanks guys

 

[rawill]

But as for o-rings there are two so I guess you could replace those, you will need to undo the nut at the end then you can slide out the selector shaft where the o-rings are. Be careful though as there are many springs and leavers in that area that need to go back together in a specific order.

Take jjhepburn's advice seriously, if you drop a spring or the collar into the bottom of the box that will end up being a lot more work than a little oil leak. The leak from there is a puzzle as the other guys have said. But you are the man looking at it and you know what you are looking at. Just double check by cleaning it off again with some engine degreaser an give it another road test.

I hope JJhepburn icomes back in on this but, I think there are two springs and the collar in there as well as the selectors. Whne you take the rod out I think the selectors will stay there ok. It will be the springs and the collar you need to be careful not to drop. The rod will be under a bit of tension and will tend to pop up towards you.

All the best

 

[jjhepburn]

Lucky I have a gear box all pulled apart (my parts gearbox) so I have taken a photo of the selector shaft which clearly shows the o-rings.

You might also want to check that the oil can properly drain out of that part of the gearbox as oil shouldnt be able to simply be sitting there to leak out.

As Robin has pointed out be careful not to drop stuff into the gearbox. This shouldnt be too much of a risk as the parts are rather large (one big metal thing and two large springs). Also as Robin has pointed out you have to be careful it doesnt all come flying out of the area as soon as you remove the shaft. There is a small amount of tension in the area (the two springs are what keeps your gearstick in the middle).

So when removing the shaft you should probably do the following things:
Undo the nut
take a note of the orientation of the other end of the shaft
while holding the internal parts in place, slowly remove the shaft
might be a good idea to follow the shaft with a piece of thick wire or a small rod of some kind just to hold everything together while you remove the shaft.

Putting the shaft back in again is a bit tricky as the splines only fit one way, you will just need to make sure its oriented in approx the same way as it was when removed and jiggle it until it slides in (don't force it).

 

[DigitalNomad]

Lucky I have a gear box all pulled apart (my parts gearbox) so I have taken a photo of the selector shaft which clearly shows the o-rings.....

Hi the jjhepburn,

Thank you so much for your help and that photo. It gave me courage to undertake this DIY (distroy it yourself) job with a bit more confidence. When I took it out, I immidiately followed it with a thick piece of wire to group all the parts together, walked to the spares shop, got both o-rings for less than 1 Euro and replaced the whole lot again.

I did get a bit worried in the end, but remembered you mentioned it might get tricky at some stage. It is all together now, and the leak seems to have stopped.

Thanks big time for the guidance.

Unfortunately my to-do list has once more got a new priority problem. Actually it is the problem that continuesly resurfaces which I paid a local mechaninc a small fortune to repair.

To keep things neat and tidy here, I have started a sepperate thread, ( https://www.fiatforum.com/uno/203262-uno-fire-trouble-changing-gears.html?p=2177722 ) and perhaps you could help me out with some pointers...

Thanks once more

 

[rawill]

Well done, JJhepburn's wire trick makes complete sense, I am grumpy I never thought of it.