Here I go again

[SwampmanLA]

Merry Christmas to all................

I purchased my 422 in February 2008. Shortly after getting it home I had tram pump issues. It seems that the check valves were not holding in the tram pump and I had to swap it out. Well it is doing it again!!! Terry sent me a new pump but I have to swap it again. Is anyone else having tram pump failures? I wonder because in two months I am out of warranty and repairs are on my dime. I love this machine it is so handy, I do almost everything with it.

Swampmanla

 

[BobRip]

Did you get the filter from PT that will allow you to fine filter the tram circuit. It is very expensive, but it may be needed. Also are you doing the periodic filter change on the hydraulics.
I have about 700 hours on my 422 and no problems with tram pump so far.
Sorry about your problems.

 

[SwampmanLA]

I have 82 hours on my 422 and am on my second filter. I did not know PT has a 'super' filter, I'll check into it.

 

[BobRip]

I have 82 hours on my 422 and am on my second filter. I did not know PT has a 'super' filter, I'll check into it.

It was priced at $700 when I checked many years ago, but it might be worth it in your case.

 

[SwampmanLA]

OK Terry and this board say that my problem is rare so with two Rare failures on a single tractor it has to be something I'm doing or the tractor itself that is the cause of the failures. The only pump that is filtered on this tractor is the Tram pump, the one that is failing. I have no way to tell if the filter is plugged as it has no differential pressure indicator so all I can do is change the filter. A plugged filter could be the cause of this failure by causing cavatation in the tram pump, I guess. So the root cause could be dirty hydraulic oil, plugging the filter and resulting in cavatation in the pump.

A few questions come to mind:
1. Do PT filters have a bypass built in them and if so what pressure is it set at?
2. If I get the hydraulic oil analyzed what particulate value is acceptable?
3. If I change the oil can I assume that my tank will be clean after?
4. Will a filter in the PTO circuit clean to oil to an acceptable level?

Oh well the kids are here to open presents, Merry Christmas!

 

[Bob999]

I have a different model tractor so this information may not apply to yours. The filter attachment on my tractor has a port where a vacuum gage can be installed so that the amount of vacuum can be monitored. (Yes this is a supply side filter and it operates under vacuum. In my experience at a cold start the vacuum can climb to 20 but when the fluid warms it drops to less than 5.)

 

[J_J]

OK Terry and this board say that my problem is rare so with two Rare failures on a single tractor it has to be something I'm doing or the tractor itself that is the cause of the failures. The only pump that is filtered on this tractor is the Tram pump, the one that is failing. I have no way to tell if the filter is plugged as it has no differential pressure indicator so all I can do is change the filter. A plugged filter could be the cause of this failure by causing cavatation in the tram pump, I guess. So the root cause could be dirty hydraulic oil, plugging the filter and resulting in cavatation in the pump.

A few questions come to mind:
1. Do PT filters have a bypass built in them and if so what pressure is it set at?
2. If I get the hydraulic oil analyzed what particulate value is acceptable?
3. If I change the oil can I assume that my tank will be clean after?
4. Will a filter in the PTO circuit clean to oil to an acceptable level?

Oh well the kids are here to open presents, Merry Christmas!

Just about every hyd filter has a bypass built in. You could also put another filter in parallel that would filter down to the 1 micron level.

You should know that the hyd fluid in the tram circuit is closed loop, and will use the same oil until some fluid is allowed to cycle through the case of the tram pump and back to the reservoir. I don't know if you have case drains on your wheel motors, but that oil is also sent back to the reservoir. If you think about it, the filtering system on the PT is not that great, in the fact that it is only filtering the charge pump oil, and it only does that when it has to make up oil lost or sent to case drains.

The PTO pump and the steering and lift pumps suck oil out of the reservoir, The reservoir is filtered in a round about way.

A PTO filter would work, and I believe someone has done that.

If you have anything breaking down in the tram circuit, such as metal shavings, rubber particles from hoses, etc, all this stuff will continue to circulate through the closed loop circuit. So even if you replace the pump, you should also clean out all the lines and wheel motors. If you are going to have the hydraulic fluid analyzed, be sure to get some fluid out of the tram circuit.

 

[Bob999]

If you think about it, the filtering system on the PT is not that great, in the fact that it is only filtering the charge pump oil, and it only does that when it has to make up oil lost or sent to case drains.

A PTO filter would work, and I believe someone has done that.

Actually the charge pump supplys the hydraulic cooler and that is continually flowing--typically 3-5 gallons per minute--so there is continuous filtering of fluid.

I have also installed a return filter on my mower so whenever I mow I am filtering the return from the PTO circuit.

 

[J_J]

Actually the charge pump supplys the hydraulic cooler and that is continually flowing--typically 3-5 gallons per minute--so there is continuous filtering of fluid.

I have also installed a return filter on my mower so whenever I mow I am filtering the return from the PTO circuit.

Those figures seem high for this reason. Charge pumps usually pump about 10% of the main pumps capacity. If you calculate the HP required to run that pump, you would come out with a 30 GPM pump, would require 62 HP, and a 50 GPM pump would require 103 HP . Other than make up oil, it does help keep the tram pump cool.

When you are not mowing, do you connect the hyd lines together? Do you remember the cost of that high pressure filter and was it rated at 10 microns.

 

[SwampmanLA]

The tram pump is a closed circuit, that changes everything. I assumed that once the oil circulated through the wheel motors it went back to the reservoir. With a closed circuit I would think the heat buildup would be horrible. Like you said, once debris is in the closed circuit it is in there for good. So if I have this correct, the only oil filtered is make up oil going to the tram circuit, unless I have a leak nothing gets filtered. Strange!!!