I have a 2000 firebird with a 4l60e auto. I’m getting this drop in rpms while wot, I can punch it around 40 and the rpms will rise then drop for a second… Feels like a shift flare. It was slipping about a week ago but I changed the fluid and filter which seemed to get rid of the slip but it has acted strange ever since. there was a bit of metal on the pan magnet but I’ve seen worse, I have a video of it right here. Also if I floor it from a stop all the gears shift fine no flares/slipping

https://youtube.com/shorts/KbZXN86arSw?feature=share

 

RPM dropping would not be slipping. Hard to tell ...could it be the torque converter locking up and then unlocking? Maybe move this post to the automatic transmission section

 

I can't tell much from the video but you would normally see an rpm drop on a shift. Or as mentioned the converter could be locking momentarily that would be a tuning issue,
Flare would not be a proper description of what you are seeing.
Frank

 

I’m guessing it’s something with the converter. Before I changed the fluid it was 2 quarts low on trans fluid and was slipping, which the dealer I bought it from said fluids were all changed… but it was pretty dirty. I’ve had multiple shops try to Diagnose the issue but with no luck.