when a moparts member "GOLDMEMBER" Jim said on my a999LU trans it is lube with trans greese on everything/fiber were soak in ATF on install. store it standing up on bell to keep front seal clean/plug both trans line fittings, install a tail shaft pug or yoke to seal from dirt/dust. good to sit for yrs till needed install new TC when installing for service.

he did my 727 to CRT-John Cope specs for the CRT VB with TF-II shift kit, greesed it/sealed it sat in my work shed for about 5-6 yrs and I installed it with a fesh TC and been bang gears daily for 50,000 miles now.

I would Indeed replace the front pump seal just insurance against seal leaks. that one sucks. the rest can be serviced in the car as needed. MAYBE do both of the shift shaft seals while on the bench.

FYI, I have pulled many a used JY trannys & trannys that have sat very long times. only had a couple that had internal seal issues, most troubles were mechanical I always open/clean/inspect filter/pan and pour fresh ATF inside letting drain down on the internals then button up the filter/pan. always start then in N so the pump fill TC & prime-lube itself right away and let it come up to temp 5-10 mins before running through he gears on it.

front pump seal and let it rip.