I have my 2000 XJ8 transmission ( zf5hp24) dismantled on my work bench. Was having some issues with slipping in forward gears and was expecting to find the input A drum coming apart. I only found one obvious bearing coming apart. I’m looking for an OEM banner kit to rebuild my trans as I’ve been told that aftermarket kits can be problematic. I was also wondering if the new improved A drum can be differentiated from the early offering

 

I know you want an OEM kit, but I rebuilt mine last spring using a kit from Cascade Transmission and it works very well. Smooth as glass. Anyway, they have a uprated A drum that has a unique retainer system, The piece looks much stronger than stock and even the upgraded stock unit. The A drum comes in at $145 or so and the rebuilt kit with everything you need...and I mean everything..is about $625. The only thing I used that was branded ZF was the filter.
I used the Pentosin fluid sourced from Amazon. It was cheaper than at my local parts store and got delivered right to the house. Bonus...