Technical Tranny issue

[a73uk]

No, nothing to do with ladyboys, its my box...

In case you didnt know, my main Uno suffered transmission issues just before Christmas, it got me home, clonking & pulling to the left as I went along, but its been sitting outside, depressed, waiting for me to sort it out since.

I had a feeling it was the N/S driveshaft tripod (the bit that locates the driveshaft into the diff) & yesterday I managed to get another driveshaft from a Fiat breaker on the other side of London, 2 hours away.

At first he showed me to an M plate Uno at the back of the yard & said "here you go!", to which I replied "as I said on the phone, I need one from a pre-92 one with the earlier 501 box, the driveshafts are different". He looked at me like I was wasting his time, then he took me to a pile of 2-300 driveshafts & asked if I knew what it looked like, I was like no.... then he suddenly said "what about this" & he took me to a Mk1 1300 SX "what about this then?" "well thats not FIRE engined mate" to which he said "nah, they are all the same mate"

I thought about it, then said "OK then, I`ll take it, but if it is the wrong one I`m not going to be happy"

"nah, its the one mate, believe me"...

One of his lackeys took it off & off I went.

Today I moved the car round the back of mine, amazingly it started first turn, the clutch did seem a bit slack (probably the pivot slightly seized) & the hand brake `cracked` off, but I gently drove into the middle of the road to reverse into the alleyway & round the back... luckily it didnt decide to lock up as I moved it round, but as I was reversing & started to turn to the right on the last bit, it suddenly pulled the steering wheel out of my hand, going onto left lock...

I went forward again & gently went back again, it was pulling as I went..

Jacked her up, drained the oil & took the driveshaft out...







Guess what... aside from both gaiters being split, the driveshaft & tripod is fine...

I peered into the diff & saw chunks of planet gear where they shouldnt be (at the ends of the blue arrows), so got my magnet on a stick & pulled them out...






As you can see, there is 1 tooth missing in action, &, bits missing from most of the teeth, those bits could have damaged other areas of the diff or gearbox. I also ringed the remaining pinion gear (on the right) & where the broken one should be (left) in the pic below.



It seems to be a cast metal gear, it wouldnt have broken if it had been machined.

Heres how it goes together, its one of number 3 thats broken:



So there you go, diff failure.... quite how she managed to move after the failure is anyones guess, but I am impressed that she did!

If any of you have a pre-92 FIRE gearbox within 50 miles of London, please let me know ASAP

 

[rawill]

Sorry we can't help, too far and my parts car is a 4 speed 1990 Sting!.

But what a great write up, very good. Congrats.

 

[a73uk]

Cheers Rawill!

I could get the diff out of Ucof`s 4-speed box (not sure if the ratio`s the same), but I`m kinda hoping to ind a complete 5-speed to swap straight in as I dont have time to be stripping gearboxes down.

This is, London scrappies dont waste space on cars over 8 or so years old, they usually go straight to the crusher, so finding one locally is unlikely.

Fingers crossed though! My Panda (4 speed) is really stuggling on motorways!

must be at least 6000rpm @ 70mph...

 

[edessex]

I had quite random diff failure with my 1985 Land Rover, front diff locked up, luckily happened at trafic lights!

You never know when these things are going to happen!

 

[a73uk]

This happened as I pulled out of a petrol station, a sharp left & I did boot it a bit, but it still got me 6 miles home, and then round the back yesterday. Amazing really.

I should have really stopped & had it towed, but I dont belong to the AA or RAC, it was 2 in the morning & I was knackered, I just wanted to get home...

I`ve had approaching 200 cars since I started driving, plus driven 100`s more, & the only other diff failure I can think of was in my old Blydenstein tuned Vauxhall VX2300 estate Mad Max-mobile, I broke 3 diffs & 5 gearboxes in that...

I had tranny failure in one of my old Uno`s too, but I didnt bother investigating it then, I just swapped boxes as they were easy to come by at the time (mid 90`s), it could have been box or diff.

Quite a few of my Jags, Carltons & Senators had diff whine & even clonks, but none ever broke.

 

[Louie Bee]

Can't remember if I kept a dif out of a late cc MK2 box I scrapped last year

I have so many boxes of Uno parts it could take some time to check

 

[a73uk]

Cheers Louie,

Hopefully I can get Ucofs one if it comes to me having to rebuild it *really hope not!*, he`s only a few miles from me.

I`ve got about a week to do it, as its parked somewhere it shouldnt be at the moment, immobilised.

 

[a73uk]

Right, a quick update & a request for help!

I managed to get hold of a 5-Speed Panda 1000S gearbox from a FF member in Kent, I also got a 4 speed box from Mr Ucof, the plan was to whip the gearbox out of the Uno, bung in the Panda 5-speed (with new driveshaft gaitors, oil seals & clutch) & then use the 4-speed box to repair the original Uno 5-speed, which I`d then bung in my 4-speed 750 Panda...

So, a couple of weeks ago I made sure I had a day free to do the Uno (its taken me this long to have time to work on it again)... started the day all positive, eager, & sure I`d have a running Uno again by the evening... took the gearbox out.. put the new clutch in & got the Panda box out of the boot & started swapping the mounts over... then it hit me... the mount mounting holes on the outer gearbox flange were different...

After initially looking at the boxes I came to the conclusion that the main gearbox castings were different, so, feeling pretty bloody fed up, I put everything away again & went in (I`d been interrupted several times, so it was getting dark anyway).

I later had a look on eper to discover it wasnt the gearbox casting that was different, theres actually a sandwich plate at the end of the gearbox, just behind the end cover, & the Panda & Uno have different ones of these. In theory I could have just been swapped over, but my confidence of the boxes being the same internally had been knocked, so I decided to strip the original Uno gearbox & replace the broken planet gear.

A few weeks have passed since then, I got hold of a complete gearbox gasket & seal kit a few days ago, & this afternoon I had some free time, so I decided to bring the gearbox into my living room & start the strip down.

Now, I hate doing gearbox internals, in fact I`ve only swapped the mainshaft on one RWD gearbox about 15 years ago & that was a nightmare, so this will be a bit of a baptism of FIRE so to speak....

I`m doing this using an early Panda Haynes manual, which is vague to say the least...

I`ve undone all the bellhousing bolts, the shift lever, & taken the detent cover, springs & ball bearings out, I`ve taken the selector cover off & undone the shift fork shaft & springs.

Trouble is, the gearbox is still only seperating 1cm from the bellhousing, then somethings stopping it. I dont want to break/bend anything inside, so, does anyone know whats holding it?

The other question is about the diff, how do you make sure you`ve got the right diff loading shims? I`m asking this because I may use the 4-speed differential complete, if it has the right ratios.

Any help would be appreciated!

Pics:

 

[Louie Bee]

I had the same when I reied to split the MK2 turbo box.

I think there is a 10mm A/F nut or bolt just in-between the parting to undo before you get it further then 1cm.

I fell out with the box and opened it with a hammer and chisel :devil:

 

[a73uk]

Nah, I cant be attacking it with the chisel, it has to go back in!

I`ve whipped the end cover off now & taken the 2 end gear sets, seem to have slightly more movement, but theres still something stopping it... cant see any bolts I havent got though. :bang:

What parting do you mean Louie?

 

[Louie Bee]

bellhousing to main gearbox lump join

 

[a73uk]

No, it feels like theres something in the gear set holding it back, I`ve now got about 2cm of air between the bellhousing & gearbox, but thats as far as it`ll go, no amount of jiggling & moving levers is freeing it

The irritating thing is, the diff is actually now loose in the casing, but I cant get to it...

 

[a73uk]

Ok, done it!

The more I`m looking at it, the more I`m thinking "this buggers never going back together again"

Also, when I took the main gear set out, 3 springs & 2 metal tabs fell out from somewhere...

Theres no sign of the missing planet gear in the diff casing, but theres quite a few shards of metal in the metallic oil sludge in the bottom of the box, luckily there seems to be no gear damage, all the teeth seem fine & theres little in the way of wear.

I cant take the diff apart as I dont have a vice in my living room (!) so I cant do much more tonight... blimey, its 12:30.. night!

 

[rawill]

Can't help, only job I have done is to replace a clutch!!

And that is not quite finished yet, Gearbox is all back in, broken exhaust stud replaced, but I am waiting for the inner axle boots to arrive, should have ordered them with the clutch.

I knew they were was leaking too!!


However, I am going to keep reading your posts, very good write up.

 

[alexGS]

I know this would have become apparent but I'm guessing the bits that fell out were the gear selector rod interlock plungers? I think they have to be lifted out with a magnet. Also the three springs/balls behind the two-bolted cover plate.

I also hate taking gearboxes apart but suggest, if you can find it, that an old FIAT 127 Haynes manual (or photocopy) might be useful. Also the 128 gearbox is similar to a certain bottom-change 'box fitted to the Uno 70 around 1988, and I believe the 127 gearbox is the same as fitted to most other Unos apart from the later FIRE models and the Turbo.

Back in the 70s the Haynes manuals showed you how to take a gearbox completely to pieces, right down to the synchro assemblies - the Uno manual does not. Sign of the times I guess but back then it seems the only economic solution was to carry out mechanical repairs yourself, spare gearboxes not being readily available!

The synchros on the Uno are different for 1 and 2 compared to 3 and 4 - the 128/127 had the 3 and 4-type synchros on all gears and no fifth gear. Sorry for the trivia but just an idea for background reading.

-Alex

 

[a73uk]

No probs rawill, glad you tackled your one! I also reconditioned my driveshafts (except the OS outer CV as its fine & I didnt want to disconnect it for no reason)

To take the inner gaitor bearing out, it helps to have some metal tubing with a 24-25mm internal diameter, around a foot long on the NS, or a long puller.

You`ll also need circlip pliers to take the tripod joint off the inside of the shaft.

Thanks Alex, gearboxes are one of those things that are easy if you constantly do them, but give everyone else a mental block, including me! auto`s are even worse...

I`ve noticed the manual problem, I have early & late Uno Haynes manuals, as well as early & late Panda, plus a Porter Uno manual. The late (red Uno, green Panda) manuals dont cover gearbox internals at all, refering you to a specialist, & the early ones arent particularly helpful either, neither even show the bits that fell out on the eploded diagrams, or mention them in the refit!

After looking at Eper, seems like they are the pads for the 1st to 2nd syncro, I think I`ve worked out which way they go back in, the issue I`m going to have is putting them back in & holding them during reassembly.

At the moment I have 2 dismantled gearboxes in my living room & I`m in the process of cleaning the external parts up ready for reassembly, so I`m not quite at that stage yet.

On the upside, the diff in Ucofs donor 4-speed is the same 15/56 ratio as my 5-speed, and its not got any real wear on the teeth, so I can swap them over complete instead of dismantling the diff cage, which is just as well because I cant seem to seperate the diff cage of my Uno`s diff...

The only concern is that the donor 4-speed diff gear has worn into the corresponding gear on the 4-speed gearset, it may be noisier when meshed onto my 5-speeds gearset as that will have a slightly different wear pattern... we`ll see when its back in...

Anyway, heres some update pics, the last 2 showing the syncro pads I`m talking about:

 

[a73uk]

After cleaning the casing ready for reassembly today, I`ve discovered a bit of an issue, the individual broken planet gear tooth must have got trapped beween the rotating diff & the casing, & being ally its cracked it in several places.

Cant see any corresponding damage to the diff teeth, but theres no other way it could have happened.

I`m now deciding whether to get this casing welded or use the 4-speed box casing (if its the same).

Like Paula Abdul once said, I take 2 steps forward, I take 2 steps back...

 

[a73uk]

My Uno`s casing is part number 91107931, the 4 speed donor: 7675346...

For some reason the 4-speed number isnt coming up on eper at all, so I`m not sure if its superceded, do any of you know?

 

[a73uk]

Well, after alot of swearing & a cock up (put it all together & realised I hadnt put one of the engagement selector shafts in), its now virtually ready to go.

3 remaining issues....

1. The clutch fork bolt was snapped in the donor boxes casing, so I cant renew or even clean up the fork shaft & bush.

2. I cant work out how to get the input shaft seal out of its tube housing without damaging it...

3. Most importantly, the diff output seems to be too far forward in the casing. Maybe its suposed to be like that, I havent got another one to compare it to & the pictures I previously took arent at the right angle to judge, I`m a bit worried that maybe that is why the casings had different part numbers & the driveshaft will rub when it goes in...

On the upside, it all turns smoothly & all the gears seem to engage, which is a huge relief, I must have looked it over 50 times before the final bolt up

 

[a73uk]

OK, after inspecting the spare Panda boxes output shaft I decided the output shaft wasnt too far forward after all :



I loosely bolted it in yesterday (not easy on your own, on gravel & using a narrow budget trolley jack with a 2" saddle!), I`ve hopefully got a hub nut coming today, which should be the last bit i need to buy.

Hopefully it`ll be working by the end of the week, fingers crossed...

One last thing (sorry Alex), & thats oil (we really should have a sticky for this!)...

I`ve got 2 litres of Tutela ZC 75 synthetic, I got it years ago, cant remember what for & didnt get round to using it... It mentions EP qualities on the back, which makes me a bit parra! What you recon? ZC75 or 20/50 synthetic engine oil?

Update pics: