ah ha! updated design.

 

Yeah, I have flywheels from 4.0 and a 4.6 and they are different the way they bolt up. The two I have are different just like in Paul's pics. On the 4.0 the hub is separate the 4.6 it isn't.

 

now for the $64k dollars question: which one's was breaking?
there were a couple post in the past about members finding cracked flywheels

 

I've seen cracks in the flex plate (FTC4607) but I've not seen any damaged flywheel/gear ring parts.

 

My guess would be that the earlier style of flywheel and gear ring was more prone to failure. Maybe that was the reason for the change in style?

 

"'ve seen cracks in the flex plate (FTC4607)" you are correct it was the flexplate

 

I saw a few pics where the flexplate had a nearly complete circle ripped at the holes.

 

yuh, thats the one i was think of

 

Yeah I have one of those flexplates ripped into two pieces. They are thin and I've read, but don't know if it's actually necessary or true, that anytime your in there put a new one in since they can have microscopic cracks beginning that you just can't see with your eye. Probably worth the extra $40 or so for piece of mind...especially if the old one has many miles on it. (flex plate that is).
About flywheels, I like the looks/feel/design of the 4.6 one best. It seems like it would be stouter but, don't know if flywheels give that much trouble anyway....maybe the ring gear.

 

SO I have the choice between TPD000050 ('04 D2) and HRC2932 ('00 P38). People say they are the interchangeable, but if I take a closer look I notice a significant difference. For theTPD000050 the large gap in the CPS coding is about 120 degrees ahead of the dowel pin (clockwise), while for the HRC2932 it is about 120 degrees behind the dowel pin (clockwise). Are they really interchangeable?