I didn't have to do main drive shaft (just shaft going to front axle) but GC2400 is bolt/spline type on main. IOW remove bolt and use wedge to expand joint to slip off. pretty sure will have to do this soon, 15yr old fan belt on it. and have to pull that to do belt.
not sure if gc1723 is same...
mower deck may be preventing full lowering. even few inches makes difference, fluid can fill glass fast. looks to me your arms almost 3inches high but may just be camera angles.
this can be your best friend
https://www.amazon.com/dp/B00DSSPCBS
you would not lose that much attach/detach, I do...
another one serviced and being hauled up road to owner.
1 deere d105 lawn tractor with shredded transmission drive belt fixed and serviced and delivered in this manner monday.
1 gc1725 with temp sensor and thermostat issues fixed and delivered tuesday.
1 deere x530 lawn tractor (nice unit...
I can say for sure when temp sensor is bad (dealing with that presently) it does not affect fuel gauge, oil pressure light, tachometer on a newer GC electronic dash series.
may help
https://www.tractorbynet.com/forums/threads/what-have-you-done-with-to-your-gc-series-2300-2400-1700-tractor-today.419677/post-7188532
sensor not arrived yet. will update when arrives.
but for you...its a ground issue.clean your terminals.clean them well.