jbinwa,
That is a weird TPI. I have seen external thread restorers that have dies for the TPI but they are $92.00 clams.
The thread file will clean out dirty threads and can straighten out slightly bashed threads, but for the most part they don't work well.
Your pinion shaft is tough material, and as you noted, was abused by a previous 'wrench'!
My suggestion would be to taper the immediate end of the shaft with a small air grinder or angle head grinder. Get rid of the ' mushroom ' on the end and you will get back to good threads.
You can use a small file (not a thread file) to clean up any threads on the end that are deformed. It's possible to use a nut as a 'faux' die if you put some Neverseize on it and run it over the damaged area a few times.
The issue doesn't appear to be bad threads but a mushroomed end on the pinion shaft. Good luck.
Stuart
