In reading a recent post, I am compelled to relate a similar problem I'm having in my IROC right now. I had the tranny (a rebuilt 700R4 from 1991) put in about two years ago and it was great....shifted at 4800 out of first and 4500ish out of second....but seemingly now it is doing both of those at 5300 (redline of 5000)....now, I also noticed that when I got the car, it could cruise at 60 mph loafing along around 1750 rpms...now, at 60, its doing about 2000 even....could my tach be out of adjustment? If so, how would an electronic tach get out of adjustment like that? A little footnote also- the shifts are still good and firm, just at the wrong time. Any help would be greatly appreciated before I go and spend lots of money (That I dont have) on this car once again.