TC40D HST oil filter seal blowing out

[fcchip]

I just performed the 300 hr service, on my 2003 TC40D, draining and refilling the transmission fluid. I can not get the HST oil filter to seal. Starts and runs maybe 10 to 30 seconds, then there is a loud snap or pop. Which is the oil filter o-ring seal being blown out and of course a very major oil leak.
Have tried three different New Holland oil filters. Also tried hand tight to carefully tighting with filter wrench, doesn't make any difference.
Tractor is currently sitting at the dealership which is not having any luck, and I believe is completely at a loss.
Anyone else have this problem? Any ideas on a repair or what's wrong? Is there a bleeding procedure to remove the little bit of air from the system when removing the filter?
I need my tractor back... Thanks in advance for any HELP.

 

[DocHeb]

Did the original oil filter rubber seal stick to the tractor rather than the filter when it was removed? This leaves two rubber seals that hit each other and don't seal tightly. No tractor experience like this, but it happened to a 1969 Mustang I owned.

 

[fcchip]

Nope gaskets are accounted for on all three oil filters. In fact the dealer thinks somehow the cast oil filter mounting bracket got warped?? His plan is to remove and machine the surface where the o-ring seal makes contact. I totally disagree. But I'm just a auto and truck mechanic with nearly twenty years experience.
I wish I could talk to a "factory" New Holland tech support person. Do they have such a service???
I don't want to have to be rude to anyone at the dealership but my patience is wearing thin. I've already had to get part numbers from a different dealer, where I didn't purchase the tractor, for them. Its a long story.

 

[Soundguy]

A straight edge will show if it is a warped surface or not...

Soundguy

 

[jinman]

</font><font color="blue" class="small">( Nope gaskets are accounted for on all three oil filters. In fact the dealer thinks somehow the cast oil filter mounting bracket got warped?? His plan is to remove and machine the surface where the o-ring seal makes contact. I totally disagree. But I'm just a auto and truck mechanic with nearly twenty years experience.
I wish I could talk to a "factory" New Holland tech support person. Do they have such a service???
I don't want to have to be rude to anyone at the dealership but my patience is wearing thin. I've already had to get part numbers from a different dealer, where I didn't purchase the tractor, for them. Its a long story. )</font>

I would just tell the dealership that it didn't leak with the factory filter and you don't want them to remove the assembly and machine it. Tell them if they do that and it doesn't fix the problem, you expect them to replace the whole assembly with a brand spanking new part and you want that in writing. That should get their attention. If they have some monetary liability, they'll be more conscientious.

Also, that filter is on the input of your hydrostatic transmission. Do you experience problems with driving the tractor, or have you gotten that far? I think there was something loose in your first new filter that clogged the system and now backpressure is blowing out your filter seal. What the dealer should do is monitor the pressure rather than Easter-egging this problem. There's also the issue with the ball popoff valve on top of the filter that bypasses when the temperature of the oil is too cool. That also might be malfunctioning.

That filter assembly is pretty tough. I hit a stump and bent mine so it sits "kattywumpus" and tore the filter completely off the mounting. All I did was to remove the remains of the old filter and replace it with a new one. It worked fine and there has never been anymore leaks.

I think Soundguy has the right idea. Those guys can check the assembly with a straight-edge to see if it's flat. After that, they need to get busy and find the real problem which I think is a plugged oil passage or other backpressure issue.

 

[farmacist]

I assume that you used hydrolic/transmission oil and NOT 90W transmission oil? Just a thought. Frank

 

[djradz]

I agree. In fact, the fact that the filter does not leak during the 10 to 30 seconds tells me there's no sealing problem. My guess is some sort of obstruction or other problem that has nothing to do with the housing or filter.

 

[IH3444]

I had all those thoughts also, is the fluid correct? Did a relief somehow stick, and not retract allowing most fluid at cold start up to recycle back through pump to warm up? Is the rubber gasket doubled up, you answered that one. Is it a bad batch of filters at the dealer, see if there is a loy number on the filter, and purchase another one from another batch from another dealer. Does the filter have a by pass spring? Is it operating properly? Soundguy is right as Jiman pointed out. The surface is most likely OK, and whatever slight imperfection that may be present is more than taken up by the rubber gasket. Good to check it tho. That's about it for me. Can the dealer check the in comming pressure to the filter? How much pressure is the filter designed for? Can he remove another filter from a machine in the yard after checking it for a lot number, and then try it on your tractor. Good Luck! /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif

 

[JerryG]

Does anyone know if this filter is on the suction side or on the return?

 

[jinman]

At the risk of droning on and on about this problem, I have several reasons to think that there might be as much as 300 psi or greater applied to the filter if there is an obstruction in the line after the filter. The HST charge pump that sits on the front of the HST transmission pulls fluid from the reservoir through the normal hydraulic filter and then pumps it out it to the hydrostatic cooler. From the cooler the fluid goes to the HST filter assembly and this to the HST transmission swashplate (controlled by the rabbit/turtle switch) and the input to the HST transmission pump that boosts the pressure up to as high as 5000 psi. I'm putting a link to a colored diagram that I posted a few years back.

Class III HST Plumbing

The large filter at 3, is the main hydraulic filter. The large line going to the left splits and is the input to the charge pump. The pump's out put (dark pink) leaves the charge pump and goes to the cooler at 5, returning on the blue line to the HST filter at 8. From the filter it goes to the rabbit/turtle solenoid valve and swashplate and also to the input to the HST at 9. The fluid feeds into the HST through the transmission mounting flange. After the fluid performs in the HST, it exits the HST at 1 and is returned to the reservoir.

What concerns me is if our gent has a blockage after the filter, the full charge pump pressure is being applied to the HST cooler and filter assembly instead of going to the HST input as it should. The gasket on the filter is serving as a relief valve. /forums/images/graemlins/shocked.gif If it is sealed up tightly enough, the cooler may be the next thing to blow. /forums/images/graemlins/tongue.gif

I hope this dealer will check the pressure at the top of the filter and assess this fault properly before something worse happens. I may be wrong, but if I'm not this problem could escalate to something much worse than it is. Hope not... /forums/images/graemlins/smirk.gif