TC 45D Rear Differential Rebuild

Charles Billings · Oct 26, 2009

That's one fine piece of equipment for $8200, that also includes a backhoe. How challenging a job was it--would you recommend that level of work to others?

dfkrug · Oct 26, 2009

jinman said:
Dave, the system relief valve is inside the hydraulic diverter valve under the right side operator's platform. It's right out in the open and very easy to access if needed.

Is it separate from any AUX or FEL valves? Comes on a tractor with
no options (only a 3-pt valve)? Just wondering what the system relief
valve approach is at Shibaura....

jinman · Oct 27, 2009

dfkrug said:
Is it separate from any AUX or FEL valves? Comes on a tractor with
no options (only a 3-pt valve)? Just wondering what the system relief
valve approach is at Shibaura....

This block called the "Combination System Relief and Diverter Valve" is the Grand Central Station for hydraulic flow. When a tractor does not have a FEL, there is a valve that is postioned to eliminate that loop from the circuit. When an FEL is plumbed into this block, that valve is rotated so that the FEL is pressurized and becomes the first system in the open-center circuit. The only other relief in the system is an emergency poppet inside the 3PH lift cylinder that will prevent shock loads when the pressure rises to about 3600 psi.

The diverter valve also diverts .8 gpm flow to the hydraulically operated PTO clutch/brake. I have a picture of it below, tucked behind an HST pedal arm. It's not the best picture, but the only one I could find from a time when I was working on my HST actuator pedals.

The HST transmission is a completely separate hydraulic system and has its own relief and plumbing that is not associated with the main hydraulic system. Power steering is also an isolated and separate system with its own pump.

dfkrug · Oct 27, 2009

jinman said:
The only other relief in the system is an emergency poppet inside the 3PH lift cylinder that will prevent shock loads when the pressure rises to about 3600 psi.

That is probably what my Kioti manual is referring to as the "safety valve",
and the pressure is in that range. The 3-pt also has a shock absorber
spring mechanism to reduce sudden loads on the hitch. The last 2 machines
I had apart (B21 and JD4300) do not seem to have either of these systems.

dfkrug · Oct 27, 2009

jinman said:
The HST transmission is a completely separate hydraulic system and has its own relief and plumbing that is not associated with the main hydraulic system. Power steering is also an isolated and separate system with its own pump.

The approach to HST design is different with each tractor I open up:
The B21 HST has its own charge pump, but excess oil from the PS diverter
adds to the charge pump flow. My JD has no separate HST charge pump
at all. It has separate PS and implement pumps, and the PS pump IS
the charge pump for the HST as well as providing oil for the PS.

jinman · Oct 27, 2009

dfkrug said:
The approach to HST design is different with each tractor I open up:
The B21 HST has its own charge pump, but excess oil from the PS diverter
adds to the charge pump flow. My JD has no separate HST charge pump
at all. It has separate PS and implement pumps, and the PS pump IS
the charge pump for the HST as well as providing oil for the PS.

NH Boomers typically have a separate reservoir/filter that feeds the PS pump. With that separate reservoir, of course they can't use it as a charge pump for the HST. The HST charge pump pulls fluid from the same reservoir as the main pump. There's a Y in the line right after the main filter. The fluid is then sent to the input of the charge pump. The charge pump's output is routed first through a HST cooler and an additional filter before going to the HST pump. The HST filter has a bypass valve in case it becomes clogged. NH figures it's better to send unfiltered oil to the HST than none at all.

skinnr · Oct 28, 2009

I would say that a someone with a decent set of tools and the knowledge to use them could tackle this job. Although it seems overwhelming to tear your tractor in half, I did not think it was that big of a job. Keep in mind I was finishing someone elses project and did not have any idea how it came apart. A good parts diagram and a web site like this I think it is totally reasonable to do in your own shop. Some sort of overhead lifting device is a must since most of these components are more than one guy can handle. Time and patience and I think it can be done.

compact freak · Oct 29, 2009

Need help! My have pushed my pto a little by over extending pto then lifting back up. The sheild was metal putting the force on the tractor. Now i can't move pto by hand without a rod in pto shaft. Sounds a little rough too when on and idles. The pto measures the same as the one at the golf course that is a little newer. What did I mess up? Tried pulling pto but could not, not sure if you can. Hoping it is just the bearing!!!! Any help, ideas???