Boomer 35 hst pressure test adapter?

[mklingenmeyer]

I’m trying to fix a 2011 Boomer 35 that’s leaking fluid from the hst.
I want to test the HST charge pressure before I split the tractor. The manual says I need part number

380003163 TOOL​

To screw into the test port. However the tool appears to be unavailable. Can anyone suggest an adapter to test this? Or know the thread size?

I just got a complete service manual for the tractor. Troubleshooting says for hst leak first thing I should test the charge pressure. I don’t think this is the cause as it leaks slightly when not running but quite a bit when it’s running. However I should probably test this before I go ahead and split the tractor.