Is a 131 Transmissions Worth the Trouble????

[Dougieb]

Hi,

I know someone that has a few 131 transmissions laying around that he wants to part with.
(Even an automatic, not that I want that. ha ha)
I have searched the forum and other places for information about swapping to this transmission.

The best information I found is:

http://www.mirafiori.com/faq/content/13 ... nsswap.htm


1) While I know that the 131 is stronger than the 124, is it worth the trouble?
Other than extreme upgrades to the engine or racing, do we need/see much gain from it?

2) I would need an "Abarth" remote shifter to keep my knuckles out of the radio.
How hard are they to obtain?

3) Is there any better information about the swap that was left out of the mirafiori page?

4) What is the opinion of someone that has done this swap?

Thanks for the opinions,

Dougieb

[divace73]

I have done this on my car, if you are not pushing massive horsepower/torque through your current box, I'd leave the 124 box in. The 124 box is such a nice box to drive, the 131 is notchier.
The reason most people upgrade is due to power increase.
The so called abarth remote is the same remote on the later 131's, the only difference being the word ABARTH cast on the extension.
You will have to cut the back section underneath the ashtray (and will lose that as well)
You may have to adjust the tunnel a little where the 131 fork ends up.

Then you will have to modify your tail shaft to fit as well, I have hear a rumour that an Auto spider front tail shaft may just swap in, but this is a rumour I have heard and not tested.

It is a bit of a headache, in saying that keep if he is going to scrap it, keep it, it is worth something to somebody down the track.

[djape1977]

also worth mentioning, 131 transmission is pretty much unbreakable. unlike 124 gearbox, i'm yet to find one that needs rebuild, or for that matter, even a bearing change

[Daniel]

I also thought the 131s tranny was more noisy compared to the spiders I've owned. The front drive shaft from
a 131 auto would most likely work as well.

also worth mentioning, 131 transmission is pretty much unbreakable. unlike 124 gearbox, i'm yet to find one that needs rebuild, or for that matter, even a bearing change
djape1977 Posts: 427Joined: Sat Apr 21, 2012 3:08 pm

I heard a story (never been confirmed) that the company who produced the 131 tranny went out of business
because this durable product and all the spare parts they had made were never used, a waste of stock.

[BEEK]

when i had my fiat salvage yard, over 20 years, i only sold 1 131 manual trans, somehow someone found a way to break the reverse idler. i cant tell you how many of those i threw away. wish i had not now, but hindsight is 20/20

[djape1977]

more noisy? i doubt although they are found in diferent types of cars so it's hard to compare. 131, 132 and argenta, which all used the "131" gearbox were sedans with far better sound insulation than 124 spiders. maybe a right comparison would be 125, which used the same gearbox as 124 but was insulated prettry much as 131 was. well, having owned both, i can say that both transmissions make hardly any sound when they're in good condition and all of the soundproofing is in place. maybe the idea that it's more noisy comes from the guys that have installed it in 124's but haven't put back in all of the soundproofing.
if you want it absolutely quiet, look for 131 transmision made after 1982. it had smaller teeth on gears so it was even quieter than originaly. it can be found in fiat argentas and supermirafioris.

@beek - my girlfriend actually managed to kill the reverse gear in my 131cl when she managed to jam it into reverse without pressing the clutch. only time i ever saw someone manage to actually put it into gear that way.

also, since there's no need to lift up or push down on the gearlever to put it into reverse, it's possible to jam it into reverse while the car is still rolling forward.

unbreakability actually comes from the fact that it was designed by ZF from germany on request of fiat. bearings are bigger, sinchros are steel, and output shaft is not on the bottom of gearbox, meaning that when rear o-ring fails, and it does after 30 years regardles if it was actualloy driven or not, not all of the oil can leak out like on 124 gearbox. there's always a liter or so left inside which is is enough for normal operation.

[Daniel]

more noisy? i doubt although they are found in diferent types of cars so it's hard to compare. 131, 132 and argenta, which all used the "131" gearbox were sedans with far better sound insulation than 124 spiders. maybe a right comparison would be 125, which used the same gearbox as 124 but was insulated prettry much as 131 was. well, having owned both, i can say that both transmissions make hardly any sound when they're in good condition and all of the soundproofing is in place. maybe the idea that it's more noisy comes from the guys that have installed it in 124's but haven't put back in all of the soundproofing.
if you want it absolutely quiet, look for 131 transmision made after 1982. it had smaller teeth on gears so it was even quieter than originaly. it can be found in fiat argentas and supermirafioris.

@beek - my girlfriend actually managed to kill the reverse gear in my 131cl when she managed to jam it into reverse without pressing the clutch. only time i ever saw someone manage to actually put it into gear that way.

also, since there's no need to lift up or push down on the gearlever to put it into reverse, it's possible to jam it into reverse while the car is still rolling forward.

unbreakability actually comes from the fact that it was designed by ZF from germany on request of fiat. bearings are bigger, sinchros are steel, and output shaft is not on the bottom of gearbox, meaning that when rear o-ring fails, and it does after 30 years regardles if it was actualloy driven or not, not all of the oil can leak out like on 124 gearbox. there's always a liter or so left inside which is is enough for normal operation.

on the 131s i've owned the transmissions seemed a tad noisy at speed in 4th or 5th and i recall hearing the same
pitch on at least 2 of them i owned a few 131s in my time.

[djape1977]

you're sure it was the gearboxes and not the differential noises you heard?

131's had a common problem with "chocolate diff syndrome", meaning that insides of diferentials were made out of brown stuff. diff bearing failures are common and result is noise coming from the back of the car at higher speeds. from what i've figured out so far about 124 spiders, later models had the same rear axle as 131 and failures are as common as on 131. way to remedy this, at least in europe, is to install rear axle from 132 or argenta. these are pretty much unbreakable. only thing i ever changed on these is wheel bearings, and i work with these cars every day...

[131]

I heard a story (never been confirmed) that the company who produced the 131 tranny went out of business
because this durable product and all the spare parts they had made were never used, a waste of stock.

ZF are still making lots of stuff.

http://www.zf.com/corporate/en/homepage/homepage.html

[Daniel]

you're sure it was the gearboxes and not the differential noises you heard?

131's had a common problem with "chocolate diff syndrome", meaning that insides of diferentials were made out of brown stuff. diff bearing failures are common and result is noise coming from the back of the car at higher speeds. from what i've figured out so far about 124 spiders, later models had the same rear axle as 131 and failures are as common as on 131. way to remedy this, at least in europe, is to install rear axle from 132 or argenta. these are pretty much unbreakable. only thing i ever changed on these is wheel bearings, and i work with these cars every day...

The noise on mine came from up front it wasn't loud just annoying on a long drive if the radio was off just a little
whine, I've never heard the same whine on a 124.

ZF are still making lots of stuff.

http://www.zf.com/corporate/en/homepage/homepage.html
Mick.

Interesting the guy who told me this was a 131 owner later on i purchased the orange 131 i had for a few years
maybe he was just trying to impress me or the story was passed on to him who knows.

[131]

on the 131s i've owned the transmissions seemed a tad noisy at speed in 4th or 5th and i recall hearing the same pitch on at least 2 of them i owned a few 131s in my time.

The 5 speed on my new 131 has been quite noisy since I got it. Last weekend I drained the oil and refilled it, I also dismantled and lubricated the shift extension housing. I'm not sure what oil was in it, but it was not very viscous and didn't smell like gear oil. It's now amazingly quiet, so much so that now I can hear the diff whine, another issue to look at.

[Daniel]

The 5 speed on my new 131 has been quite noisy since I got it. Last weekend I drained the oil and refilled it, I also dismantled and lubricated the shift extension housing. I'm not sure what oil was in it, but it was not very viscous and didn't smell like gear oil. It's now amazingly quiet, so much so that now I can hear the diff whine, another issue to look at.
Mick.

I never did much to them other then changed gear oil on 2 of the 131s I just assumed it was the aging parts
making the noises. I'd sure like to find one of these shift extensions for my 124 project any leads for a unit in
good shape? djape1977 found one on ebay for me but it looked pretty beat up, he at least found one and i appreciate
that was thinking if i waited i might find something in better condition or is there sources for the parts to rebuild
them?

[Curly]

I agree with Divace73 in that if it's to go in a standardish or mildly modified road car, the 124 box is a much more pleasant box to drive. Most of the pictures in that article on the Mirafiori site seem to have been pinched from an item I wrote for another website (now deceased) when I was installing a 131 box in my Spider. There's quite a bit of work to do, and I don't think I'd bother if I was doing it again.
Because of competition eligibility regulations, I still have a 124 box in my AC coupe which has withstood the rigors of over a dozen tarmac rallys and it's a quicker, smoother shift than the 131 in my Spider. I did however, purchase and fit an alloy finned 'sump' from Germany for the 124 box as it gives it another pint of oil, the casing a bit of extra rigidity and some cooling benefit.

[spiderrey]

Hi Curly, who sells that sump?

[Curly]

Hi Curly, who sells that sump?

How's your German?
Address and phone numbers are at bottom of these fitting instructions.