Have you found the solution? I have same issue p0735-ff code. Problem occurred after I serviced the transmission. Apparently it wasn’t serviced before for a long time. But it was running trouble free except some lag when taking off from a stop. Lag is gone but this problem started. Fluid level has been checked many times. Initially I thought it’s the after market plastic pan/filter as filter neck/tube may be smaller and not sealing casuing internal leak. Tried metal pan conversion kit with separate filter but same problem. Car drives fine in general and I have traveled 1000kms in a day. But when it has to go through a lot of gear changes in traffic the problem occurs. Only fix is turn of the car and on again. If you have found the solution please advise.