The rpm's went up to the red mark and back! I eventually got it up to 60 mph though. I haven't checked the tranny fluid, but, my VX was fully serviced, by Isuzu, in September. I'll check anyway. I've owned 4 other vehicles that were lifted and fitted with even bigger, heavier tires and smaller engines than the VX. And never have I experienced that before! Except, when my clutch was going out in my 4runner.