The FL1 jatco oil level is checked from cold. Switch it on and leave on tick over to warm up. When auto oil temp is between 35 and 45 degrees C, run it through all gear lever positions, pausing in each for 2 seconds. Then leave the engine running on tick over. The level plug is underneath the auto. Put more oil. When its at the correct level oil will flow out the level hole. All of this should be done with it on level ground. Does the oil smell burnt or look brown/black?
All of yer resistance readings are out. This normally happens when the meter battery is a bit flat. It might be the meters not accurate. The resistance range is posted on ere loads of times by me. Its also in the text below the video on YouTube.
I agree there's some valve block seals. We don't get major problems with block trouble but it does happen occasionally. Slamming gears is normally low oil or solenoids or barrel connectors coming apart. Oil level check and resistance check is what main dealers do first. Also code check but theres not many code option available for faults so yer don't always get one.
resistance video = https://www.youtube.com/watch?v=VTmdkDuKZ6A