Update: had my machine repaired at a New Holland dealer. New transaxle housing, bearings and seal. Expensive repair but glad I have it back and also glad I didn't attempt 😅
Thanks for your reply. I was coming to a similar conclusion as you and I just don't have the time to do this and possibly don't have the skills 😄 I found a New Holland dealer about 40 miles from me, I'm going to take it in and have them repair.
I've noticed a creaking and popping noise coming from the left rear axel area (same side as differential lock pedal). I've noticed it previously but only once in a while but this week while Bush hogging my field it was happening a lot. I'm not sure if this is differential related or other...