When my truck shifts with the tq converter locked sometimes it bounces. It feels as if someone was driving a stick and coming off the clutch too soon. Usually 3-4 bounces, but when I was towing recently it started the bounce and wouldn't stop untill I let off. It much more noticable uner meduim to heavy throttle, wot throttle its usually pretty quick shifting.
Different tunes do this differently, IDP's are so bad violently bouncing I can't drive the truck, Vivian's does't do it at all, no converter lockup, and Tony's who's I'm currently using sometimes does it and sometimes doesn't. Depends on the tune. But Its never as violent as IDP's. Just a few bounces.
Any idea what this is? I don't want to eliminate lock-up just want it to lockup smoothly like it sometimes does all the time.