Don't fool around with trying to run solvent down the shaft. It won't get down inside the guts of the PTO where the real problem lies. Spend the time and effort to service the PTO properly. It's a bit fiddly but not all that difficult. I've serviced many of them over the years. To do the job, I recommend you have on hand a quart bottle of 91% Isopropyl Alcohol (available cheap at any pharmacy, including Walmart), a roll of paper towels, a cotton terry towel that you won't mind ruining (to use as a work surface), some cotton-tipped swabs, a small plastic tub to soak and clean the parts in, and some hand tools (especially needle-nosed pliers and pointy tweezers). Put about an inch of alcohol in the plastic tub and drop the parts in it as you remove them. Soaking them in the alcohol will help remvoe the old dried-up grease and crud. If you need the genuine Ten Tec PTO rebuild instructions, email me at my_call_sign at qsl dot net and I'll email you a PDF copy. Read it thoroughly, several times, and become intimately familiar with it before you start the job. It will go much easier that way. Refer to the diagram early and often. Earlier this evening, I serviced a spare PTO that I pulled some time back from a parted-out Triton IV. The job took me about 2 hours total time. Bench-tested and working fine. Sealed up in a plastic baggie until needed later.