nothing for nothing, but the NAG1 has to be filled professionally (its based on temperature since there is no "dipstick" and one has to be purchased separately) so if a dealer did the flush you're good. Otherwise - Transmission fluid filling increments.....Hoping for a little help from anyone. I have a NAG1 transmission that shifts fine in every aspect, except when it goes from 1st to 2nd. When it shifts it slams really hard. It almost feels like being rear-ended. Any ideas out there?