This kit provides wide open throttle 3 to 4 upshifts for TH-700-R4 (4L60) transmissions. This is not provided on most TH-700-R4 transmissions (except Corvettes and some IROC's). Most TH-700-R4 transmissions will downshift from 4th to 3rd gear at about 3/4 throttle. This allows the transmission to remain in 4th gear at full throttle. Does not work on 4L60E electronically controlled transmissions.
