2019 Kenworth T880 X15 with dual gearboxes. Truck has had gradually worse power steering over the past few weeks. When we checked it today, at idle it would barely turn and when I revved it up slightly it turned like normal. We replaced the pump, and it made no difference. We can see the pump is working by seeing the fluid in the reservoir go up and down. Is there any other way to test which gear box it could be? Or can we bypass one at a time? From the dealer, parts are a few days out.
Are you absolutely sure it has the correct pump & did you change filter? Was the fluid cooked/ turned dark?
It is the correct pump, changed filter and fluid seemed fine.
Changed the primary gearbox and that fixed it