Fiat 124 Spider gearbox help needed !

[miro-1980]

Gents,

My 124 Spider 1980 gearbox recently got bad.

Initially the problem was that the gearshift lever was moving way to widely to change the gears accurately, We have changed the springs and rubbers in the gearchange lever mechanism which took care of this problem but I always had a feeling that the 1-3-5 engaged "more deeply" while 2and 4 engaged in a more "shallow" manner. Occasionally 2 would resist on a downshift from 3rd (this was taken care of by longer and making sure that the clutch is fully depressed) The 4-th would occasionally disengage on a road bump, and with my foot off the gas pedal. Recently (after a transmission oil change) the problem got worse. the 4-th will disengages quite often and on quick downshifting from 3rd to 2nd gear there is clear resistance as if the clutch is not depressed. It still is manageable with more time taken to synchronize when shifting down from 3rd to 2nd and keeping my hand on the lever when in 4rth but it seems to require immediate attention. By the way even quick shifting from 1st to 2nd is no problem shifting and shifting to 1st, 3rd and 5th is just fine.

I have a feeling that 2nd and 4th do not engage fully. My current analysis is that this is a bearing retaining plate got loose preventing the gears from engaging fully and thus causing the problems. This was a typical problem with Polski Fiat 125 p which had a similar construction gearbox.

I am facing this problem and want to ascertain if this can be easily fixed and if not, what gearbox I would need to buy (and where ?). I have found one guy that has a 124 spider gearbox with the "small bell housing". I would like to get it and put my bell housing on it. Does anybody know if this will work without modifications.

Can anybody confirm what I have gathered so far and answer some detailed questions on 124 gearboxes :

1/ there were two types of 5-gear gearboxes for 124 spider - early and late model ? when did they change ?

2/ Aside from internal differences they had different bell housing sizes (200 mm and 215mm) ?

3/ Are the bell housings interchangeable between early and late model gearboxes?

Any advice , suggestions?

Miro

[Guy Croft]

There were indeed 2 types of 5 spd gearbox with bellhousing on the 124 Spider. The early one - as fitted to the 124 1608 Spider (and Coupe) and the later one as used on the 1800 and 2L versions. You can play 'spot the difference' but you'd need to have them side by side! The later one married to an engine with a bigger diameter flywheel than the 1608 and thus had a roomier bellhousing. Don't know how different the gearboxes themselves were, suspect pretty much the same but they are not interchangeble in the sense that you need the early box and bellhousing with the early engine - and the late with its bellhousing on the others. QED.

Not that I rate that early gearbox anyway, they are, as they say in the USA 'way weak' (I've exp numerous breakages and so has virtually every owner who likes to change gear fast and get going..) in fact I shall stepout of my normal restrained language remit and say they were a real 'waste of space' and the best thing to do by far if your engine is an 1800 or 2 liter is convert (literally, because it's relatively easy) to the later generation (post 1973) 5spd box from any 131 TC model. That, again must be fitted with its particular bellhousing. It marries straight to the 1800 or 2L TC engine with the same starter and clutch cable assy, rear mount and rubber coupling. You do need to shorten the front propshaft section and get the assy balanced and you do need to cut open the tunnel at top and driver side to accomodate the larger gearbox. However the work is well worth the effort because it is a far, far stronger box with better ratios too.

GC

[miro-1980]

Guy

Thanks Guy for the detailed explanation. Now I know what I face if I do not fix 124 spider my gearbox.

I have two spare 131 TC 5 gear gearboxes complete with original bell housings I could use. But I really am very restrained in conducting modifications if they require such modifications as cutting the tunnel open. This would be my last resort if no other method can keep the car on the road.

Miro

[TR-Spider]

Miro

I mounted the 131 gearbox to my 124 spider without much cutting of the tunnel.
Instead I cut out 30 mm from the straight part of the Abarth extension of the gearlever, had the casing welded and shorten the internals. (on Guys picture the gearlever casing is elongated to suit some other car)
Then the gearlever just sticks out like the 124 one (well, you loose the ashtray...).
Some slight deformation of the tunnel however is necessary, in the rear on the side to clear the rubber coupling (hammer) and in the front to clear the top (piece of wood and a hydraulic lifter bends it upwards ).

The 131 gearbox is a wonderful piece, slick and precise to operate, realy a joy to drive...

Thomas

[Guy Croft]

Very helpful tip, Thomas, thanks as usual!

G

[miro-1980]

Thomas ,

Great idea!

Thank you very much, this is something I want to look into.

Any pictures ?

Miro

[TR-Spider]

Hi Miro

sorry, I dont have pictures from the swap itself.
I did the swap before the start of the"digital age", i.e. before I owned a camera...
The only thing I can provide is a picture how the gearlever sits now inside, and where to cut out the piece in the Abarth-elongation (shown on my spare-box), and how the crosssection of the cut looks like .

Thomas

Größenänderung Wiederbelichtung von IMGP1081.JPG (107.68 KiB) Viewed 17057 times

Größenänderung IMGP1079.JPG (90.06 KiB) Viewed 17057 times

Größenänderung IMGP1080.JPG (102.15 KiB) Viewed 17057 times

[miro-1980]

Thomas,

The pictures do indeed look very encouraging ...

I will look at my ashtray location to see what I lose ... ( I do smoke and need one LOL )

The more I look at this the more I think this looks like a very good option ... if I can't get my gearbox fixed.

Miro

[Guy Croft]

Since looking at Thomas' photos I have a feeling that the 4 door 131 Mirafiori 1600 & 2 liter (not Mirafiori Sport also known as 131 Racing in Europe at the time) had a shorter gearbox remote gearchange assembly, for ID purposes it was not marked/made by Abarth.

Can anyone comment?

GC

[miro-1980]

G!

I contacted a friend in Serbia with a lot of Fiat experience who said as follows:

" 1/ As far as i know, there is one type of 124 spider gearbox, and two types of bell housings. bell housings are interchangable. if there's any other differences between these two types than I am not aware of it.

2/ Gearbox from Fiat 125 special (wide horizontal taillights and 4 square headlights) 1608ccm is exactly the same. Earlier 124 units had the same small bell housing as 125 special for 205 clutch plate and later units for a 215mm one as 131 and 132.

3/There is a rumor that Fiat Campanola (jeep like thing they made for army) has the same gearbox. This I haven't personally seen so it might be worth checking out .... They're still widely used in Serbian army and there are many on scrapyards..."
very interesting Interesting is the Fiat Campagnola lead. Does anybody know ?

I am not sure if my Serbian friend actually swapped small to large bellhousing and actually fitted to the 1.8 -2.0 engine ... but I wouls like to get to the bottom of it

You said they are not interchangeable, but do I understand it right that I cannot take an early gearbox with small bellhousing , take the small ballhousing out , put a large bellhousing and fix it to late model 124 engine?

Miro

[miro-1980]

Since looking at Thomas' photos I have a feeling that the 4 door 131 Mirafiori 1600 & 2 liter (not Mirafiori Sport also known as 131 Racing in Europe at the time) had a shorter gearbox remote gearchange assembly, for ID purposes it was not marked/made by Abarth.

Can anyone comment?

GC

=========
GC ,

I remember that the reson we have put a latemodel dash to my 131 instead of the original one was that we wanted to use the gearbox with longer gearshift assembly. The dash originally in this car had a tunnel element which was for a gearbox with a shorter shift assembly. So it looks like there were two shift assemblies a shorter one for early models and longer for late models. It maybe that the early Mirafiori gerabox could fit the 124 tunnel without modifications. I will try to speak to one of the German dealer who supplies me with 124 parts about this as wellas about interchangeability of the bellhousings and 124 gearboxes. We will see what they say.

Miro

PS I will look in my garage . I think I have two gearshift assemblies : one on a gearbox with Abarth written on it and spare assembly ( no gearbox to it) without Abarth markings. ( this may be the one we did not use for my 131 that came from a 4-dr Miriafiori ). Will measure and post the results. ?

[Guy Croft]

Yes, please do with side by side photos,

G

[Simon]

I've just joined the forum and thought I would just add my experience on this subject since I too have a 1980 Spider 2000 that developed a gear box problem (the common jumping out of 4th on the overrun)

I acquired a 131 sport 'box from Guy years ago but had held off fitting it since it looked like a quite a bit of work to modify the tunnel. I was eventually forced to do the job though when the car was needed for an urgent filming job, and in the end the actual conversion wasn't as difficult as I had thought.

I'm not sure if all Spiders are the same but mine has bolt-on tunnel top. After removing this and offering the 131 'box up it was apparent that only the rear section of the tunnel top was required, taking it back to the rear edge. I had to fabricate a new rear gearbox mount, out of the original and one off a Lada I had lying around. I suspect there probably is a factory Fiat variant that will fit correctly though. With the 'box in place the remote change housing poked through the tunnel by about 25mm which meant the original flat tunnel cover, which was now too short, couldn't be refitted. In the end I cut the mounting flange off it an fabricated a new raised top with an extended rear vertical section to cover the hole (see second picture.) I wish I had take more pictures at the time but I was in a rush to get it back on the road. I also had to shorten the front section of propshaft between the donut and center bearing.

The first picture below was taken a few years ago at the time I was trial fitting the 'box and suspect I might not have needed to cut so much of the rear of the tunnel away. You can see the section of tunnel cover flange I retained. The second picture was taken this evening whilst in the process of stripping the interior for track use.

The tunnel cover removed and the tunnel sides and rear trimmed.

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Hybrid tunnel cover fabricated from the lower flange of the original.

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