its in a 92 chevy truck ith 3.08 gears and when it hits overdrive, overdrive is really soft and there is only a 200 rpm decrease from 3rd to over drive. when im going 70 mph the tach is at 2900 rpm, and on my buddies truck with the same rear end gear, his tach is at 2100. whats worng with my trans?? it was rebuilt 30000 miles ago and the convertor is 10xxx miles new. it feels like there is no overdrive but just the convertor lockup. please help!!