The lube turns into hard pieces and gets stuck in places. I would start with seeing if there is air going from the compressor to the air dryer. Small...
If the air compressor is indeed not making pressure I would check the governor first. Its mounted on the compressor. And the unloader could be stuck...
The cab brace should fold out and lock when the cab is fully open. I had a truck that was giving me hyd function issues I swapped the control box and...
It shouldnt. It could just be a stored error that will self clear over time. There are wheel sensors that detect slip, some valves on the frame rail...