Hard Shift after start up in morning

Recently had to replace some of the rubber lines that connect to the trans cooler/radiator dfid not loose that much fluid (less than 10 oz).
When engine is cold and I start it up shift into 4th or drive it is fine but when i let off the brake it feels almost like a hard shift.
Wondering if this is because trans fluid is so cold but seems like the clunk or hard jerk would happen when you shift into a drive gear not when you release the brake pedal....

 

Maybe the transmission fluid was a little low before you replaced the lines?
If so, 10 oz could be “a lot”.

Normally, on these trucks. When the fluid is cold, it will shift hard into gear.
The worst of which is 4th going into 5th (OD).

Hard shifts on deceleration can be a sign of low fluid. I’d check the fluid level.

 

Cold fluid high idle