My frirnd (a fellow 6.9 owner was telling me about a vacuum actuated part that goes on the side of my injection pump that can change the shift points on my c6 does anyone know what he is talking about so I can find out more about it before buying it for the build

 

On the c6 the pump is on the rear lower portion of the transmission,mine was on the driver side, and a vacuum line coming out,also has a sliding pin going threw it , which when bent will cause a lagging shift or no shift at all (ask me how I know, dropped 2 feet off a drop and hit a boulder ) on the c6 it's called a vacuum modulator, should be one nut and a plate holding it in place, if you remove it you should expect to lose a little tranny fluid

 

if its for a c6 , it should be linkage operated ..... like a kick down cable, the vacuum operated cylinder should be for cruise control....... maybe I could be wrong....... never seen a c6 with vacuum operated kick down ....

 

Thanks 4x4manonbroke I just don't know how to make my 93 cruise work yet tho he said he could change when the trans shifts that's why I am confused, what you said would make more sense

 

In my c6 I never figured out the cc, but I just tested pulling off the vacuum line and driving it and only had first gear, unless I manually shifted into second, so I'm assuming that that's it, they also sell different ones with a high vacuum pressure needed to open soooo