Fixed my trans that let go at BG. All it was: pin/nail on shift shaft broke and it went into neutral on the 2-3 shift. Luckily it didn't tickle reverse or I might not be typing this now. Anyway put a backup trans in with my same governor that shifted at 5000 in drive (I liked that so I can slow car by shifting where I want for 10.00 index). NOW it shifts at 6400 both shifts in drive. Was shifting at 6800 but I backed modulator all the way out and got it to 6400. Why would new trans shift so much higher with SAME governor that shifted at 5000? (picture of pin that broke)
I thought the modulator was for part/ light throttle up shift and the governor handles WOT shift points.
Was the detent system working on both transmissions? Minor variations would be valve body, couple hundred rpm.. A lack of a functional detent system on your first trans, vs a working detent system on the second could explain that much rpm difference in the shifts. JW
Detent working on both. Yeah, vacuum modulator mainly for part throttle but I have found adjustable red stripe one do affect WOT but only a max of 300-400 rpm. Not sure why but maybe affects line pressure? I'm wondering if new trans was set up with more line pressure than previous one. I'd like to try another governor but can't remove it in car (trans is tight fit in tunnel.)
Modulator senses engine vacuum, which should be at or near zero at WOT. Not sure how the modulator could affect the WOT shift point 300-400 RPM??? The governor sets WOT shift points.
Not upshift in auto range can occur till governor pressure overcomes throttle pressure. An increase in line pressure would increase both of these. So your governor pressure is down.....maybe internally leakage.......or your throttle pressure is higher......different valve sizes, or different springs in valve body can effect shifts by a few hundred rpms too.........could be a combination of a few different things here
