Leaking PS gear box at top-need help

For my 67 273 I did manage it in car with not much problem.
Trying to recall correctly I believe the return valve is mounted with a couple of "low head" bolts and I took my time to keep from rounding them off.
I just used the closed end of a typical box wrench.

Good luck... wish I had done it sooner.
Not difficult or expensive and now dry as a bone