Volvo FH13 iShift problems with shifting and uphill derate

Hello everyone,I drive Volvo FH 13 with D13C engine and iShift trans. 800 000 kilometers on tacho and truck started to develop two problems which are not connected I hope.

First problem started 6 months ago when climbing uphill full throttle or on cruise control truck derates and gives a message Stop safely,Engine System Failure.
Sometimes message comes up after few seconds going uphill at full throttle and sometimes when you pass the hill and road levels,depends if you have light or heavy load but it always happens. Since then I changed Oil pressure and crankcase pressure sensor but nothing changed. Also no codes under dash. Truck has good power and always same consumption.It does not use any oil or coolant or mixes them.
Problem disappears when you turn off cruise control or move foot from from accerelator.

Second issue started yesterday.If you try to start from second gear there are noises in transmission like gears are grinding and also during the driving truck sometimes misses the gear,or lets say it shifts from 5th to 7th gear but gear is not engaged from first try,then it tries to shift again and then it suceeds.I think this is related to air pressure, because it shifts few gears good while air pressure is on maximum and when air drops a little problem starts.


Sorry for lots of text and if I wrote something bad,I don't speak english on daily basis so my grammar or spelling may be bad or not so good like in other forum topics