I reversed the upper and lower 3/2 way valves in a effort to either clear or implicate said valve(s) with respect to the clunking transmission. Transmission still clunks, but the clunk is now more pronounced at the 3-4 upshift and less obvious during downshift. (If coasting to a stop, the downshift clunk occurs just prior to coming to a stop. Or, it will occur if pedal pressure is reduced after the 2-3 upshift.) As best I can determine, the lower 3/2 valve receives source vacuum. It is closed at idle, and opens with slight accellerator pressure. This appears to route source vacuum to the upper valve, which opens at about half throttle, routing vacuum to the EGR valve. It also appears that both valves affect transmission vacuum. The role of the 3/2 valves with respect to the EGR valve is pretty clear. Not so obvious is their affect on transmission vacuum. Since the vacuum valve on the IP serves to reduce vacuum as the throttle in increased, what is the exact function of the 3/2 valves? Does the upper valve just exist only to operate the EGR? Or do both valves affect the transmission?
At the transmission modulator line, I have 15" at idle, 6" at half throttle, and 0" at full throttle. Should the next step be to R/R the 3/2 valves?