Jerk when accelerating in same gear from low to high

I am getting an issue with my truck freightliner cascadia 2016 (manual transmission 13 speed)
When i am shifting in high gears . When the truck gets into higher gear the rpm goes down and when i accelerate is a jerk .so i had to slowly accelerate to avoid the jerk .
Mechanic checked it but shafts are good and transmission oil is good too .

Getting no idea what is wrong.plz help

 

Could be several things. Hard to say without driving, but don't rule out slack in the power divider.

It takes a beating with heavy footed drivers

 

I just got new deferential last week . There was play in the deferential. Thought that would fix the problem but no
One more thing i noticed was the problem only comes when the temperature is high suppose more than 10 celcius .
In winters it drive good .

 

Hello how you fix this issue