I have a 1994 IHC 4700 with a T444E and an Allison 545. My problem is the shift timing. It has a two wire modulator on the side of the transmission.

Currently is shifts to 2nd at 1800 RPM and 3rd at 2100RPM. If I power the modulator, it shifts at 2600RPM 1-2... Login to read more.