D17 Series IV Loader Hydraulics Quit

These issues all existed before and my Ford loader worked fine. Now its dead. I changed the filter to no affect. I "think" the fluid levels are correct. The rear rams/arms move, albeit slowly. I was thinking I should take the pump off and down to the shop to be rebuilt, but am not sure that is my issue.

Can someone walk me through the idiot steps? I would be very grateful.

Thanks.
Steve

In thinking about it I've also become convinced that I'm not getting pressure out of the rear aux connections via their hoses up to the loader valve manifold. I have both control handles between the seat and fender to the rear position, which I think is how they are supposed to be.

Your pictures were VERY helpful. Thank you.

I wouldn't rush into taking the pump off just yet.
Some of those symptoms sound similar to what some others have experienced; especially the hydraulics not working after sitting idle for a while.
In fact, a local guy that has a D17SerIV had this very same problem (his tractor has a Do-All loader)

One recurring theme is that the Traction Booster valve or linkages are causing this condition.
A side effect of the valve hanging up is constant whine from the relief valve (on the valve stack) & increased oil temperature.

Look underneath the flat plate where the valves are mounted. The TB valve is the spring-loaded return plunger type and can hang up. Kinda hard to get at, but try spraying some WD-40 or the like on the stem, and work it back and forth with a rod or wooden dowel.

Another source of trouble is the linkages/bellcranks underneath that come from the lift arm on the right side. Sometimes the bellcrank can rust tight to the stud that it's supposed to pivot on. There's also some linkages in front of the rear axle housing that should be looked at to make sure they move freely.

Hope this helps

Here's a picture from under the plate.

Here's one from the rear...
The "bellcrank" is right ahead and to the right of the downward loop in the return line.

Here is the current status of my problem. I am making progress and thankful that you are so helpful.

The rams are now raising and lowering properly. However, the tractor has a Ford loader on the front fed by the the left rear aux outlets. It is not functional. The left valve control piston under the seat appears to work fine, but I don't get any action on the arms and bucket from the control manifold mounted up by the seat. A couple of things occur to me. Is the pump very sensitive to fluid level in case its slightly low? Could I have some blockage affecting only the aux outlets? Can a DIY'er flush the system? Also, the TB return line is dripping, but I can get a wrench on it to tighten it.

Please don't give up on me. :) Thanks!

Steve