Looking over in an intermediate hub replacement that I just got in the mail and it does not have the rectangle center lube hole in the bushing. Looking over the old one it doesn't have it either? Both are from a 2001 model supposedly. Can I get away without this lube path or is replacing the bushing to the newer design even possible?

I am also missing the five inch split plastic circle that goes in between the output carrier assembly and the reaction carrier assembly. Is this a necessary part? This is the second 4l80 I ran into without it inside.

 

i think your 80e new bushing is early style I looked at all mine and the do have the rectangle. The plastic thing is a noise suppression and no it is not required,
I don't have an early tube to compare . But have 1/2 a dozen center lube types and they do have.
But I am pretty sure though never paid much attention as I do so few early non center lube maybe 3 in 10 years if that , I honestly never paid much attention other than to make sure same as old one. But I don't keep those I special order when i get one of those units,
So My best guess is the new one you have is for an early non center lube 4l80e.
Wait a minute is that not the rectangle blurred at the top? in which case you are just looking at it upside down ?

 

91-96 center support bushing is Durabond 02101
97 up is Durabond 03118 (34044c generic) and will look like this:



Early 91-96 has the rectangle slot in it an looks like this: