Turbo constantly revs on 2006 Ford F-350 Super Duty

Recently had new head gaskets (and a lot of other parts)replaced on my f350 with 6.0L engine, it runs fine until I hook up trailer with equipment loaded (about 5000 lbs) the turbo starts revving when throttle is pressed the more I press the gas pedal the higher it revs, if I try to get up to speed the truck will start to overheat. Any help is appreciated

1 answer
The turbo is exhaust driven so the more diesel is pumped through it the more it spins, I would have the shop that replaced the head gaskets check their work because this ford diesel should easily pull that load without overheating