I took the tiller off the 123 along with the gear box and mule drive to put on the hydraulic lift 125, that I had to take the push blade off.
Opened two cans of worms

was as careful as I could be but popped the gasket on both tractors. The 123 I just changed the filter and Hy-tran two years ago, so I saved that fluid, but I never changed it in the 125, so I guess it wasn't a complete loss.
Picked up a filter at CARQUEST and gaskets and fluid from my dealer. Not cheap, but if you want the best you pay the price for Hy-tran. Don't matter much, our IH dealer won't give a break on bulk oil

so I needed the parts today to finish up this mess and move onto the next one.
Everything is back on, except the tiller. Looking forward to not struggling lifting that tiller manually.
Also mower with the 782 today, and it seemed to get hot. Now I have read about tractors getting hot before, but how do you tell between hot and normal?
I mowed for what seemed like an hour or so, and popped open the hood and couldn't keep my hand on the air cleaner for long. Filter was clean, full of oil and it was only 80* I never had a closed hood and side tractor other than the 1650 and that seems ok. What do you think?