New to the forum, just picked up an 85 C20 Suburban, 454 with a th400, runs pretty good except the trans shifts late and kicks hard, 1-2 anywhere between 35-50mph. Don't have a tach so I don't know what rpm. I was told this was a common Chevy problem. The previous owner said he'd changed all fluids except trans. So I'm gonna changed fluid and filter soon, but I wanna make sure I don't have to dig into the trans multiple times. I unplugged the kick down solenoid to make sure it wasn't stuck in passing gear, but it still kept up the problem. Could the vacuum modulator or governor be causing my problem?