A factory replacement I/F transformer is not longer available after some 50 years from production. This doesn't mean they are not repairable, however. There are threads here at AK where their restoration is discussed. Restoration be tedious and patience will be required of the restorer, too.
For this reason, you should take great pains to ensure that the ferrite cores used in them remain intact. Without proper tools and techniques, at this age, they need to be gingerly dealt with. If the FM tuner section is working now, it is best to leave it be. That is, do not attempt to replace the tuner's tubes or even to move them to other positions - especially the I/F section along the right hand side. This guaranteed to mess up the alignment. The impact to you is that the tuner will not be as sensitive, may not operate reliably in FM Stereo mode and may have a distorted audio out in both stereo and mono settings.
If you can't tell they are working, it would be best to describe what it is that's leading you to believe it isn't working properly.
Cheers,
David