Discussion: Dana/Spicer 3 Speed Powershift

[chansey]

I have a 1989 1500Z Trojan Loader that that has a Dana/Spicer (Clark-Hurth) 3 Speed Powershift transmission and the transmission is being overfilled with hydraulic fluid. The overfill is about 4" above the full mark on the dip stick and then hydraulic fluid starts running out the bottom of the flywheel housing. Hydraulics work fine until the hydraulic tank runs low.

I have two inspection holes on the FH cover and there is no fluid around the outside of the torque converter or other wet areas that I can see. Fluid is not flowing as though the fluid is under pressure but leaking through a seal leak. I've looked at the flow schematic and the only connection between the transmission and the hydraulic system is that the transmission drives the main hydraulic pump.

I rebuilt the main hydraulic pump and replaced the front bearing and seal. This had been a major source of a leak into the transmission, so much so that the breather and fill tube would over flow. After re-installation, the leak stopped for a few days and then started up again. I was able to back off the bolts on the pump and verify that the pump was no longer leaking.

Looking for input from someone who has experience with these transmissions or can identify the source of the hydraulic fluid entering the transmission. Been chasing this issue for a very long time ..... help me put an end to my misery.

 

[funwithfuel]

Do you have a dry disc parking brake or an integrated wet brake?
What kind of flow do you have from pump case drain with full throttle full load. Anything exceeding 5% of free flow volume would be a red flag against the pump.

 

[chansey]

funwithfuel

Thanks for responding ..... Things have changed and for no reason at all, but to answer you questions, the brake is a dry type and is an external drum mounted outside the transmission.

As for the pump, I have no faith in it at all. Because of the bearing failure, the was some wear in the gear case on 1st and 2nd stages. Had no other option just can't afford the German pump.

Ran the loader for a few hours today. Really have to rev the engine to get the hydraulics to work. Curling the bucket is extremely slow. Have no power steering to speak of and very jerky. Need movement of the loader to help with the steering.

The hydraulic leak is still present, but much less than before. Doesn't seem to leak when the machine is running as there are not drops present. When the machine is stopped, it drops about 1/2 cup of oil.

I would like to replace the pump if I could find a US version, or re-plump another pump as necessary. The manifold is the difficult part as the ports on the pump align with those on the manifold and supply hoses connect to the manifold.

 

[funwithfuel]

It looks like a split gear pump. Common enough. With the manifold for connectivity. There's a vendor in my area who could reverse engineer from the original core. Mostly just for measurements. The closest places to you would be Colorado or Utah. The company's name is force America. They might be able to help you. I don't know of any other vendors that will step up like these fellas have.

 

[funwithfuel]

By the way, why does the end plate have the pump cavity open. I also see a thrust plate and sealing that should be "internal

 

[chansey]

The coupling drive gear bearing and seal were completely torn up. The front cover and plate were removed for inspection. When I purchased the loader, the 4 bolts holding the pump housing to the transmission were off completely. I believe that they were troubleshooting the hydraulic leak into the transmission.

The pump is available in Germany at a price of 4 times the value of the loader. The manifold (yellow part) is more of a problem. There are numerous pumps that are 3 stage but the outputs don't match the ports on the manifold. I would entertain placing parts in other remote locations. Have not been able to locate any used units anywhere. I am located in New Mexico and there are any salvage yards or other sources to find an alternative.

Really looking for suggestions on how to overcome the situation. One possible solution would be to make adapters to fit between a replacement pump and the manifold. Suggestions are welcomed.

The machine is very good condition and can't see scrapping it.

 

[chansey]

This is the pump drive from the transmission. The three washers do not belong on the shaft. Moves the seal out so that it does not function. Bearing and seal are off the shelf at Parker. Only the shaft portion of the bearing was found.



Drive housing and first pump stage. Due to the bearing and seal failure, there is some wear in the pump stage. I was not able to find metal debris in the bottom the transmission sump. Former owner must have cleaned it out.

 

[funwithfuel]

I would think any reputable pump shop could mill you one out, using the old one as guideline. It's just a gear pump after all. They just need body thickness, rotor diameter etc. All dimensions you can provide over the phone. Worth a few calls to save some coin.

 

[chansey]

I tend to agree that this pump is not unique or special. There are numerous 3 stage pumps available That have capacities similar to the one being discussed. The two outer pump gears are the same. The center one is much smaller. The gear drive is involute, however it is available.

I need the function/configuration of the manifold explained so I have a good understanding of what I need to do to eliminate it. The pump has 3 suction and 3 discharge ports as they enter the manifold. On the discharge side of the manifold the center port is capped off and the manifold has a 3/4" hose fitting and one test port.

Took a look at other Trojan loader pump setups and the 1500Z and 1700Z are the only ones set up this way. All the others have a large single pump just like most loaders.

This is what is illustrated in the parts manual, however it is not the same pump that's on the loader.

Thanks for the help thus far. You have confirmed what I was considering.

 

[funwithfuel]

Without knowing your machine , I would guess the manifold distributes oil for your various functions. ie. Steering, brakes and work. Without a manual, no other choice but to follow hoses to respective consumers