Hi there, I understand that an AU trany has 7 solinoids. Can anyone tell me what the function for each one is? I have heard that some people suggest locking S4 or S5 to tighten transmission changes????

for firming up the changes you add a electronci shift kit which chnages the voltage sent to the s5 solonoid allowing greater lin pressure hence firmer/fatser shifts
no idea on the number of solenoids in the box can be more than 5
i could be wrong hough

there is actually no S5 marked on the valve body but its the "damper" soleniod, its the largest one in the box and its located looking up on the back right. another fault for pad shifting or going into limp mode (3rd gear) is S1 which is the shift soleniod.