904 dragging in reverse

Took it for a little 200 mile run from Lansing MI to Saugatuck MI all two lane. It ran great. Shifted fine. It was just over 90° outside. The transmission ran hot went up to 210°. But there were curves, hills and several stop signs. Every time it dropped below 200° I hit a stop. Tried to cruise at 65 mph but hit 85 a few times. That was 100 miles going. The last 10 mile got in traffic and could only do 55. It cooled down to 175° and only went to 200 for a short time the rest of the trip. Driving home I did 60 mph most of the time used a gallon less of gas. 3.91 gear with a Gear Vendor unit. 3200 stall converter. Going to slap the 3.55 back in this week.
Thanks for the tips. They all pointed out something to look at.IMG_20210606_103144.jpg