Rpms jumping while engine is cold

I’ve posted before I can’t find the thread but I saw some other people had this problem. I have a 16 5.7 with 130,000 miles and noticed this whole winter when I drove before it got to about 35% of the engine temp it would jump at the end of the gear usually 2nd or 3rd until I let off the gas pedal and then got back on it to get through the gear. Anyway I changed my tranny fluid and bam that was the problem. No more Rpm jumping. So anyone having that problem could try doing that.

 

Was that the 1st fluid change on the truck? Just trying trying to learn as much as I can.

 

It was the Second change. I did the first one whenever it said to in the book. This one I did at 130k. Not on purpose lol