My '70 500L has a 126 tranny with a 500 bell housing. I'm swapping the bell housing back to a 126 so I can fit a 650cc engine. When I pulled the bearing covers off, they had O-Rings on them which were mashed flat along with a lot of hard dried up sealant. I cleaned it all up and I'm ready to install the 126 bell housing. Do I use new O-Rings on the bearing covers? There is no slot for the O-Ring so I'm guessing this is not a 126 requirement.

Anything I need to know to do the bell housing swap? Or is it as straightforward as it looks?

Hi Marcus,

Hopefully, someone will chime in with more knowledge than me but I can add that the bearing housings on my 126 differential had the rubber O-rings when I pulled it apart.

Agreed that there is no groove in bearing housings, altho, the bell housing and transmission do have that beveled edge that the O-ring sits in. Mine also had RTV to make the seal. I asked recently if I should use just the O-ring alone or with RTV. The consensus was to just use the O-ring. Here's that thread (which you had initiated, BTW): https://www.fiatforum.com/500-classic/350726-general-use-sealant-gaskets.html

Since the previous owners saw the need to use RTV to stem the flow of gear oil, I'll be putting in new O-rings and hopefully, they will do the job themselves.

Sorry, can't help with the bell housing swap details.

Cheers,

-bob

PS: What part of Mass. are you from? I'm originally from NH.

Use the O rings. Its a bigger pain in the arse to install after you have assembled everything. Stops oil leaking out of the box and into the axle boots

I saw the bevel in the tranny case after I asked my question. Looks like it was made for it, so in they went. I don't want it to leak and hope to not have it apart again any time soon so I did use sealant from the O-ring out, on the flange itself.