The stock 4L80E center support assembly is used in the 6x because of its already great strength. This is one of the parts in the 4L80E and 6x that comes from the old TH400 transmission.

Because the 4L80E uses a 32-spline output shaft, just like a TH400, our NP203 needed a new input gear. If you’re using a TH350 or 700R4 transmission, you will likely not have to disassemble the ...

Of course, the Gearstar Performance Transmissions Level IV 4L80E HD transmission and Yank Performance Converters’ “Pro Yank” billet 10.5-inch converter are the headliners, but additional and ...