131 transmission swap in the 124

[jaymanire]

I am installing a 131 transmission in my '80 FI 124 (which came with an automatic ). Please don't ask why I chose this path because I am already second guessing that decision...so just go with it. I sourced the trany and shifter extension housing (among the other required parts) from Midwest; however, I am not sure that I received the correct shift extender. Forgive me if this is a stupid question (still learning as I go) but is the so-called "Abarth" shifter extension that bolts on to the 131 transmission the same extension housing as the one with 124 manual transmissions? Is there a difference? When I attached the extender that I sourced from Midwest to the 131 transmission, I can't shift the gears. They shift fine with the original 131 shifter on it, so I am confused about what's going on. The only thing that I can conclude is that the extension housing I purchased does not work with the 131 gearbox. Any ideas?

I would greatly appreciate advise and coaching from anyone that has experience with the 131 trans swap.

Yes, I've read the mirafiori link...several times --> https://www.mirafiori.com/faq/content/1 ... nsswap.htm

Jay

[rridge]

There are two styles of 131 transmission shifter, direct and remote. Direct is mounts on the top of the transmission case over the shifter rails. It is the only style shipped to the U.S. Remote extends the shifter location rearward so that the shifter sits roughly over the driveshaft donut and operates a foot that extends into the main transmission housing. "Abarth" is the original style of remote shifter and that word is cast into the housing. Not sure it was ever used in anything but a real 131 Abarth. That style was later copied and used in late 131/Brava coupes sold in Europe and Australia.

Like all Fiat vendors Midwest knows a lot about their parts, has handled them and knows what it has sent you. That the place to start asking questions. Jon Logan, who often shares a service bay at Midwest, is one of the best Fiat gearbox experts in the country.

[lanciahf]

Jay I did this conversion last year. The 131 Shift extension is different than a 124 and yes the trans should shift fine with the extension. As Richard suggested I would call Jon

[jaymanire]

So I finally mounted the transmission. Now I am trying to connect it to the existing draft shaft (which was previously connected to an automatic (so length should be fine for this swap, right?), but it’s about 4” too short. What am I missing? See pics in link below.

https://photos.app.goo.gl/LVZ6GxELshj8dYY88

Thx,

Jay

[jaymanire]

So I finally mounted the transmission. Now I am trying to connect it to the existing driveshaft (which was previously connected to an automatic (so length should be fine for this swap, right?), but it’s about 4” too short. What am I missing or doing wrong? See pics in link below.

https://photos.app.goo.gl/LVZ6GxELshj8dYY88

Thx,

Jay

[rridge]

As you can see, the end of the shaft poking thought your donut does not relate in any way to the locator bearing on the yoke of the transmission output shaft. I'm guessing that either you do not have the piece that connects the splined shaft of your automatic transmission front drive shaft to the back of the donut or you have the wrong one. Take a look at this picture:

https://www.flickr.com/photos/rridge/9646446211

In that picture, the item on the left is the front driveshaft from an automatic Spider. It has the center bearing already mounted on it tail. The second piece is the connector with the yoke that fits the driveshaft side of the donut. It has a splined cavity on the output side that accepts the splined front end of the auto driveshaft and a larger female bearing surface that fits over the locating bearing on the transmission output shaft.

[jaymanire]

I am finally close to completing this project, but I ran into an issue I do not know how to resolve. I purchased from Midwest the front portion of the AT driveshaft and forward yoke assembly like the ones in the links below.

https://www.midwest-bayless.com/Fiat-12 ... at-u8.aspx

https://www.midwest-bayless.com/p-6686- ... pd-u8.aspx

However, the front driveshaft will not slide into the forward yoke assembly. I've tried many many times, but it seems that the splines on the driveshaft do not fit the splines on the yoke, at least on one end. If I flip the yoke assembly around and insert the shaft the other way, it slides right in. However, I know this cannot be the correct orientation of the yoke, based on the parts catalog pictures and how it is supposed to attach to the transmission output shaft yoke assembly. I've had included some pictures and short videos in the links below.

Can someone please explain what I’m doing wrong. Maybe I still do not have the correct yoke assembly and/or drive shaft, but this is what Midwest sent me.

https://drive.google.com/file/d/1vtAz08 ... 4FfOe/view

https://drive.google.com/file/d/1g0QwCp ... 8KAQv/view

https://drive.google.com/file/d/1eAGBg_ ... n_IZO/view

https://drive.google.com/file/d/1VHIYhV ... IUW9U/view

Thanks,

Jay