whats rpm range should my tranny shift at.cause first gear seems to drag out a little more than it should.first gear shifts at 2500 thru 3000 rpms and seems like it has a loss of pull past 2000 rpms.also when i cruise around 40-60 mph tranny likes to shift up and down from 3 to 4 gear a few time until i trottle it up some any thoughts on how to fix this.