Yes, the bellows got replaced after I removed the rear half of the transmission.
I tried to do the replacement in situ, but the bellows screws into a threaded piece which slid away while trying to get the threads started--must be some trick that no one's told about.
With the rear half (extension)on the bench the bellows got screwed into position, and now--no oil leaks.!
One problem to be aware of is:
make sure the assembly that slides on the splined rod still freely slides while the transimission is being re-assembled.
Now my intermediate speed hold doesn't work, but I can live without it!
Not too easy a job while on your back, especially replacing the rear gearbox mounting bracket--which is spring-loaded.