i got a 95gt with an auto, ever since i've bought it the trans hasnt been the best, it'll shutter and not wanna down shift at times, but i can get a trans flush bout every 6 months and it'll be fine, what i wanna know is what would be the best to put in the trans to make it run the smoothest and last the longest, i was thinkin a royal purple trans flush with some other kind of additive