First of all thanks Kidshorsesme! Coming across your post guided me very easily to replace my flex plate from home, also. Took 1 full day solo, all bolted back up 5am to 5PM including trips to shops and breaks. Not rushing it.
I sourced my replacement by matching up part numbers you mentioned in your post. Ebay had me sorted for AU $167.06 including postage from Lithuania. Flex plate looks excellent and arrived within a few weeks.
Replacement: 16420300512 / 6420300512? (searching 6420300512 gives many results)
https://www.ausjeepoffroad.com/forum...9&d=1704671171
https://www.ausjeepoffroad.com/forum...8&d=1704671171
Worn/replaced:A6420300012
https://www.ausjeepoffroad.com/forum...7&d=1704671171
Background- Mine had flat spots from before I purchased the car. I ended up chewing the starter motor out on a bad spot within a week of getting her on the road. Replaced the starter motor to get me by for a while. Then carried a large 1/2" ratchet with 27mm socket to turn over the motor. If it so happened to stop in the most warn spots on the flex plate
Tools I needed outside of common hand tools:
>27mm on long ratchet (turn over crank bolt -front of motor pulley)
>T55 on a 3/8" drive (all bolts on the Flexplate- torque converter bolts and crankshaft mounting bolts)
>Grabbed a nice solid sturdy trolley jack from super cheap auto (coupled with a cheap crappy one i already had to back out the gearbox)
Surprisingly easy, my rough replacement steps and order:
1. Car ramps under front wheels and level it with stands under rear diff. Secure it well make sure its stable. (do this the day before so everything isn't 6000 degrees). Remove battery negative.
2. remove front and rear propshafts. Mark locations for correct re-fitment.
3. loosen all gearbox bolts while everything is still supported. can get to all of them without doing anything crazy. Just use a good assortment of flex drives and long bits.15mm hex i believe. All but one behind the auto trans lines can be done. Left some in with a few turns so nothing fell apart for the next steps.
4. clear all the tranny stuff that wont let you roll it back without snagging. dipstick tube, tranny lines and cap them -they'll keep dripping,selector cable bracket and linkage.
5. through the inspection gromet hole in the bottom of bell housing undo all the torque converter to flexplate bolts T55s 6 of. Rotate crank bolt 27mm to get them all out.
6. get the trolley jack supports in and make sure its sturdy. I fixed some timber to the top of mine and secured it to the trans support cross member. Tied the trolley jacks together. So, they both rolled together, I didn't have to be under the car when rolling it back too.
7. undo the last of trans bellhousing bolts leaving the crossmember bolts to last. undo crossmember bolts once everything else is out. Check over again to make sure nothing else will be an issue when rolling back.
8. Undo the crossmember bolts to unibody and roll it back (only needed 150 mm or so. Only dropped the cross member to clear underside by 5-10mm and rolled it back. Used screw drivers and timber to separate it off the rear of motor + ratchet strap to the trolley jack to reverse it back gently without being under the car.
9. Undo 6x T55 bolts and replace flex plate. I used a piece of timber on teeth of the flexplate wedged against the bell housing to stop it turning over the motor.
10. Reverse order of steps and call it a day.
Some pics:
Rolling back the gearbox- ratchet straps
https://www.ausjeepoffroad.com/forum...1&d=1704673227
Trolley jacks setup
https://www.ausjeepoffroad.com/forum...1&d=1704673227
Old vs New
https://www.ausjeepoffroad.com/forum...1&d=1704673227
Cheers!