Trans Lurches in three gears but not in OD 2001 GM

[Logman55]

Strange problem with my 2001 GM. When starting from a stop, the tranny lurches through the first three gears until it gets to about 50 and the OD kicks in. If I turn the OD off at the stop, and then accelerate normally, it does not do this. I had an 89 GM with the AOD trans and the lockup at 50 had a pronounced clunk, almost a bang. This trans has been very smooth up till now. I thought the OD had no effect until about 50, so I'm wondering if the OD is trying to engage before it's set point and that's the "lurching" I'm feeling.
Thanks!

[sly]

check fluid level. you may have a small leak somewhere and it's drained a bit much. If it's low, top up with Mercon V.

[cld783]

2002 p71 od comes on at like 35mph under light throttle. i can tell because if i turn off od it flares. that or its something to do with the torque converter.