Transmission fill cap coming apart

[Little Fred]

Brought home a FMD . Early but unknown year as of yet. Checking oils I realized the transmission plug was not loosening but tearing itself apart. I "tightened" it back up and the split went back together. So I'll keep it covered until I have a replacement in hand, but what is the best approach to remove the old one? Maybe a punch?
I will put wd40 or similar on it, which I regretfully had not done from the start.
We also brought home a Super Major backhoe loader and an IH 504, all project tractors.

 

[Majorman]

Looks like you have a lifetime of restoration in front of you, they are pretty tough old machines! The plug is made of brittle metal and if it has seized there is little you can do to free it up. You could take the selector plate off and work on the bench, that would stop any debris falling into the gearbox.

 

[Little Fred]

Thanks @Majorman looks like we have our work cut out for us! But at $200 a piece we decided to go for them. Saved them from the scrapyard where most of the others in a collection were going.

 

[560Dennis]

a field full of diamonds

 

[Little Fred]

a field full of diamonds

It was. We were not the only ones to buy the tractors to keep, but many went directly to the scrapyard. We missed a Minneapolis Moline, not sure of the model, and a Massey Ferguson 35 (if I'm not mistaken) diesel.

 

[560Dennis]

It was. We were not the only ones to buy the tractors to keep, but many went directly to the scrapyard. We missed a Minneapolis Moline, not sure of the model, and a Massey Ferguson 35 (if I'm not mistaken) diesel.

Well don’t be sad , proceed !