Transmission Identy

[halg]

The transmission is the last piece I need to complete the drive train on my 69 coupe. Most of the Fiat parts and pieces I have were inherited from a good friend. He was a Fiat fanatic, ask Mark, he hauled, I think it was, 3 flat bed truck loads from his 5000 sq ft shop. I don't know where the trans I want to use came from. On the side of the main body is Fiat 4B 124 A 100 4220677 Chromodora. I know that a lot of the time these numbers are just for the casting. This trans only has 1 fill plug(not 2 as is talked about using the wrong one to fill with)it is labled livello olio with an arrow.It has 3 electrical devices, 1 on the side just above the fill port, 1 on the top just infront of the split at the rear of the case, 1 coming straight out the back. The other thing that might be an issue is, I have read about a larger bell housing on some transmissions. What were these used on? Was it for a larger flywheel? Whoever the PO was they put the spring on the bottom of the shift lever together wrong and had nothing to hold the shifter up. Fixed it by stuffing a rag under it to hold it up. It also must have had a leak because it has 2 gaskets on the bottom plate. I think this trans will fit where I want to use it.I have a trans case that came from a 72, it bolts to the 1608 engine I am using. I have the sheetmetal that goes between the engine and trans and it matches this trans. I of course don't have 3 sets of wires going to the trans area. This is probably way to much information, any insight would be appreciated.
Hal

[manoa matt]

Hal,

As you know the engine blocks, cylinder heads, and chassis numbers are well documented. I don't think the same can be said for transmissions. The early cars, 1438cc and 1608cc had smaller flywheels and smaller bellhousings. The 1800 and 2L versions had larger flywheels and larger bellhousings. The main gear box unit is the same and can be interchanged with the bellhousings.

Three electrical devices: The one at the rear of the unit is the backup light/5th gear switch that triggers the white back up lights, you will need this. The one on the side above the fill plug is the gear engaged switch, while the one on top is the fast idle switch. You will not need the fast idle switch unless you plan to run a carb with that function. The gear engaged switch is wired into the diverter by-pass relay, the diverter by-pass thermo switch, diverter by-pass control valve, and the delay switch/relay.

The fuel injected transmissions only have one wire for the backup light switch. The other two wires control emissions devices, and are usually only on carbed cars.

There should be a tiny drain plug with a square head at the very rear of the unit. There is an extra chamber back there that oil can spill over a casting wall and not return. Many owners do not know this, and don't remove and drain this area when replacing the trans oil.

[halg]

It appears that the important piece to have correct is the bellhousing, so that the starter location is correct for the flywheel being used.I have a Hollander Fiat parts interchange written in 1982. The identy of some bell housings can be figured out. I have 4 bellhousings. One is for sure a 1438 4 speed, the other three ??? The exchange book says that 71-75 coupe, 71-78 spider, and 79-81 spider use the same bellhousing. The sheetmetal that goes between the engine and bellhousing that I have matches the 3 bellhousings. The 1438 starter location is toward the center approx 10mm indicating a smaller flywheel. My assumption is that the larger bell housing moves the starter away from the center for a larger flywheel. Does anyone know when that happened. I don't think they changed the back of the block so the four mounting holes will be in the same location for all bellhousings. The interchange book says that the starter changed in 1979. It would be possible to move the starter without moving the bellhousing. Since the 2L came out in 79 I assume it had the larger flywheel. If anyone has information to confirm or refute the above assumptions please respond. I don't want to get this all assembled and have the starter not engage the flywheel, which you cant see, measure or feel. It takes electricity.
Hal

[manoa matt]

"The 1438 starter location is toward the center approx 10mm indicating a smaller flywheel. My assumption is that the larger bell housing moves the starter away from the center for a larger flywheel. Does anyone know when that happened. I don't think they changed the back of the block so the four mounting holes will be in the same location for all bellhousings."

Yes, all above is true.

1.8 liter and 2Liter flywheels and bell housings are the same size, however flywheels up to 78 had 10mm flywheel bolts, while late 78 and all 2L flywheels use 12mm bolts.

For performance, you can mount an earlier small flywheel to a later car that has a large flywheel, you just need to drill out the 10mm holes to 12mm. However the clutch and friction disc are smaller and may not be up to the torque.

I would mount the engine on a stand using the side motor mount. Mount your flywheel of choice, and bolt on a bellhousing. Now you can test fit the starter and see if it will engage the ring gear. Then any of the gear boxes can be bolted on.

[spiderrey]

I always thought the 1438 bell housing was smaller then the 1608.

[halg]

It appears that the large-
Halsmall difference is only where the starter is located.

[So Cal Mark]

it was/is smaller. Any of the bellhousings will bolt up to any of the blocks, but the small bellhousing won't clear the large flywheel and of course if you use the small flywheel/large bellhousing you're going to have to get a hand crank

[halg]

Have done as suggested, moved the engine to the side motor mounts. Instead of mounting the bell housing, which I couldn't see inside of, I only mounted the sheet metal that goes between the block and bellhousing. I mounted the starter to the sheet metal piece. The pictures show I now have some confidence that all the pieces will work together. Thanks to everyone for their help and suggestions.
Hal