Hello guys! An extremely long time lurker but never posted before. Long story short, I have myself a 2010 FG falcon that originally had the 5 speed auto. The 5 speed milkshaked so I saved all my pennies and bought a zf6 to put in it and used Hootons harnesses to avoid changing the entire body loom. She's all in and changed from P,R,N,D.
After using FORscan and figuring out the PATs programming I got it started and she drives and changes through all the gears, Hooray!.
My main issue now is, especially in the higher gears, on low throttle, the RPM's surge a lot. You can't feel it surging but you can definitely hear it and see the RPM's bobbing up and down. I've driven just over 1000kms (long drives all in a week) and the problem seems to just be getting worse.
This issue usually only occurs when the RPMs are below 2000. I don't believe it's fuel, ignition or vacuum problem as it idles completely fine with no misfiring and on my long drives I achieved an avg fuel consumption of 7.7L/100km. When I put the foot flat it has plenty of torque and changes the gears no worries. It's as if the transmission is hunting, or surging. This is my first automatic vehicle and I'm already starting to hate it.
I've seen similar threads/topics but no definite answers. I also believe my zf6 shifter is fkd because it doesn't go into "performance mode" and every time I open the drivers door it beeps at me and displays "transmission not in park" on the dash. However I believe that is a separate issue from the surging I'm getting. I'm going to install a new shifter hopefully on the weekend if I can find one and hope it fixes that issue. I'm also going to give the zf6 another drain and fill (2nd time) to see if that changes the behavior but I don't think it will.
I've taken all sorts of drives with it and have no DTC's (fault codes) showing on FORscan. I've had a little play with logging the live data but to be honest I have zero clue what I'm looking for. This only happens when at cruising speed (gentle throttle) or when I'm trying to go up hill the surging gets worse, almost as if it hesitates to drop back a gear. I should also mention the shifts from 3rd-4th feel quite odd. I'm going to try and upload a video of it and try to link it here. I assume no codes probably means the solenoids are okay? I'm really hoping it's not the torque converter. Please feel free to ask many questions and if anyone has experience anything similar please let me know. I'm hoping to use this thread to diagnose, fix and actually report back to what the issue was and what fixed it.
PS. I also want to thank you guys for helping me over the past decade with fixing the falcons with your awesome knowledge and experience, cheers.
