80 torque converter

I have a 80 L82 automatic. Everything is factory stock. I heard tell that the 80's had lock in converters. It registers 2400 at 55 and 2700 at 65. When i drove it last i noticed that 55 was 2600 and 65 was 3000. It consistantly did one and now only runs on higher rpm. It must have a 3.55 rear end? But it sounds like the lock in conveter is messed up? What happens when they mess up? Is it safe to drive? I bought it not to long ago and it had 47000 miles. I changed the trans fluid when I got it, It looked like it had never been changed. It was really clean though with no metal once so ever in the pan. The fluid is clean and full. Thanks for any help!

no harm will be done if the lock is not working. back when they first came out there were many people that didn't like the way the lock would engage and disengage so the dealers would just disconnect the wires to them

thanks man, it seems to started working right again?
and i love your car!