Weird shifting issue
This all started a couple weeks ago at our track/dyno day. I ran down the track 4 times and all was great. On my 5th run I went to leave the lights (4x4 boosted launch) and when I took off the truck was down on power. Comes time for the first shift, it hangs at 4K rpm for a few seconds and the bam slams into gear the second shift was the same and I let off and coasted to the end. I thought maybe it was a fluke and tried running again with same results. Went off to the side, pulled trans dipstick, fluid smells and looks good. I leave the track go out driving around in 2wd, trans shifts great even at wot. Have been driving around the last 2 weeks with the looney and it shifted great. Tried to do a 4x4 boosted launch yesterday just for the heck of it and same thing that happened at the track. It took off like it was bogged down, got to the first shift and just hung, then bam it will shift. I put it back in 2wd and it started doing the same thing in 2wd now! Pulled over took the looney out, put srl in and bam full power, shifts great. This leads me to believe it is in my looney tune, but why did it just come about one day out of the blue? Sorry for the book, but any ideas? Tranny issue, tune issue or something else?