Technical 500 gearbox in a 126?

[Cocodrillo]

Hello, first post here, hope you can help?
I'm trying to find out if a 500 gearbox and bell housing is compatible with a 126? I have the chance of getting my hands on a complete 500 unit including drive shafts but am unsure if it is a direct bolt-on swap.
The box has '126 AB' on it, also '4107991 9A'.
Any help much appreciated.

 

[gadge]

The 500 box will fit an air cooled 126 but if you have the water cooled BIS version then you'll have to swap the bell housing over. The 500 also has a different ratio differential aswell so the gearing will be affected (slower top speed)

 

[Toshi 975]

Hi coco the only 500 gearbox that will fit a 126 would be from a 500R. Easy check is if the starter motor mount is at the top or side of the gearbox. Top is 500 and no chance , side mount is ok if you have an aircooled.

 

[Cocodrillo]

Thanks for the replies, the starter mount is at the top of the bellhousing, so it's not going to fit. Are the innards the same though? I know that the driveshafts are a different length but it's the innards that I really need. It is an aircooled 126.

 

[Toshi 975]

The 500 gearbox will be non syncro and the internals are not interchangeable with a 126

 

[FIAT126]

If the gearbox you are looking at has 126 stamped on it, then it should be a 126 one.