H55 tranny differences?

[powderpig]

OK, so. I have a built in 2018 H55, part number 33030-60450. I have a broken front bearing support, which is what also supports
the Throw out bearing. Looking in a couple of different parts break downs. The part number for this is 33131-60040, and the seal part number is 90311-32013. Which is also the same parts numbers for the later H42 4 speeds in the late 80's 60 series.
According to the parts break downs.
Well in comparing the two, the seal on the newer H55 is bigger, both in out side and in side diameter. outer diameter of h55 is 47.5 mm vs h42 42.5 mm, inside h55 31mm vs h42 27 mm. Housing are a bit different as well, the bolt holes all line up, but
the H55 housing has some oiling slots just above the seal hole.
So, with these differences, how are the part numbers the same? Toyota does not work this way, I believe the parts diagrams
are worng. If that is the case, how does one get parts for something the parts catalog is mess up on?
Crazy.
Yes I need parts, but do not know who I can turn to to help. Local guys are scratching their head as well.

Robbie

 

[cruiserdan]

4 speeds up to March 1986 used a 33131-60020 retainer and a 90311-28004 seal. If memory serves the "28" in 90311-28004 denotes the diameter as 28mm and the "32" in 90311-32013 denotes the diameter as 32mm. After March 86 the 4 speed uses the same part numbers as the H55.