Pontiac G6 Slip/Bang tuning it out
I have an 07 Pontiac G6 with a 3900 and a 4 speed Front wheel drive transmission. It has developed a problem where if you are stopped idling in drive, and you attempt to take off briskly, it will come out of low, rev, and then bang back into gear a second or two later. If you take off slowly this doesnt happen. From my reading it appears this is caused by a seal that causes an internal pressure leak and it simply isn't holding enough pressure while sitting there idling in drive. I changed a spring in the valve body supposed to help with this issue, but that just altered its behavior a bit, it didn't actually fix it. I really don't want to take this old car apart if I don't need to, it just isn't worth a lot and I don't need it long term. I think I can crutch it for a while with tuning if I can figure out how to. The transmission functions normally otherwise, and the pan is whistle clean inside. I have determined if I pull it down into manual mode, you can take off so hard in low that it will spin the front tires without coming out of gear, so it appears to be holding a lot more pressure sitting there in manual idling, than it is sitting there in drive idling. I just cant figure out what to change in order to create more pressure sitting there idling in drive. The two modes, (D vs manual), use different shift patterns, (X vs Y), but the shift pressures are identical in them. I have read some conversation about folks changing the force motor current settings and stopping this problem, although no one who wrote about it really seemed to understand exactly what to change them to. The only Force motor chart I seem to have access to is "commanded pressure vs temp" with pressure axis in KPA across the top and temp down the side. Does anyone have any input on this that might help? Thanks
