no power on a loaded take off

[ramsey]

heres my issue,  at the ending of the day  on the last load on a very muddy work site my 2000 mack vision cx613  really struggled to take off loaded from a stop . still continues to this day,  changed air filter, had mechanic check clutch to see if its slipping  ,he said it's good and not needing adjustment.  the transmission  shifts normally,  not over heating,  rear end temps are normal. truck just hasn't got the power to take off loaded and it's even sluggish empty,  dont know if a spring came off the pressure plate or could it be a joint, turbo sensor, turbo,  I really have no clue any thoughts would be appreciated . it does put black exhaust out when shifting,  not a real lot but does for about 5 seconds per year shifted

Edited September 5, 2020 by ramsey
forgot so.e details

[tjc transport]

i would check fuel pressure, and turbo boots for boost leaks. 

[ramsey]

I could see turbo boost leaks, but I wouldn't think fuel pressure  would change that fast within a hour from running normally  to no power  . I could be  wrong.  I'll change my fuel filters and see

[tjc transport]

if the fuel pump gives out you will have low fuel pressure and no power. i lost a the fuel pump on my 99 driving down the road. 

went to take off from a light, and could not make 40 mph. 

i tried making it the two miles home, and was only doing 15 mph by the time i got in the yard. 

pulled the fuel filters and the primary filter was only half full. 

changed the pump and the next day i was back walking away from the t800 with C15 engine

[OldRedMack]

Definitely pressure check the intake manifold.