That's the most common cause, but anything that deadheads the pump will blow the seal or split the case. Could be a stuck relief valve in the loader control or jamming the TPH lift arms under lift pressure, even. But a faulty quick-connect hose coupling is the cause about 9 out of 10 times. If you have the Chinese QC's, I suggest replacing them with better ones from one of the brand name manufacturers of couplings. Tommy can send them to you, even down under.