I'm wanting to flush the old oil out of some new too me (old) attachments.One of them is a mulcher high flow. I was wondering what others have done? With that said i was just thinking of putting attachment on the machine and take off return line coupler and putting into barrel to catch spoils.With 20 to 30 gal(high flow) flow a mintue that could get messy fast! Or just take both couplers off the attachment use air while turning drumb by hand,etc.? Got different machine and hydraulic oil.Always wondered how guys did this with rental attachmnet.Looked to be a problem to me. Also the thought of bad hydraulics motor and getting metal debris in the machine.
You can use a spare pair of couplers to avoid taking them off. I use air, it might even turn the motor over, and run the hoses so gravity drains the fluid out with the air flow. Dump a quart of 5-30 or whatever you have handy and blow that out if you want to be careful. Drain it into a clean barrel and see what pans out for metal, water etc.