D6R modulating valves repeatedly sticking

[ZacharyMartin]

I have a d6r ADE00695 with transmission issues. From what I've heard it had a converter go out and it contaminated the fluid, caused tons of issues with the modulating valves. It's supposedly gotten a new converter and 2 transmissions across 2 owners. I can't imagine the factory filtration system would allow fluid to flow with big enough chunks to cause valves to stick, I'm wondering if I have some pressure bypasses that are opening and allowing junk to flow through. I've been toying with the idea of pumping it all through a low micron fuel filter with a pump, but I feel as though it should be able to filter it out on its own. I think there's a suction at the bottom of the transmission that can be accessed by removing a cover, not sure how to check it without dumping 150L on the ground (park with the rear up high on a steep incline?) and I believe the filter for it is the one against the hydraulic tank? Any help on how to remedy this issue would be greatly appreciated, this is my first piece of equipment and I definitely wasn't expecting breakdowns every 2 hours of run time. Thanks

 

[Nige]

Have an oil sample analysis done and look at the ISO Cleanliness Code numbers would be my first thought. That would give you a clear indication whether or not excessive amounts of particles are circulating in the power train oil system.

I think there's a suction at the bottom of the transmission that can be accessed by removing a cover, not sure how to check it without dumping 150L on the ground (park with the rear up high on a steep incline?) and I believe the filter for it is the one against the hydraulic tank?

The answers to these and lots of other questions are in the Operation & Maintenance Manual. You really need to get hold of one ASAP. Search for Cat Publication reference SEBU7298. If you can't find a used copy on eBay or similar you can download a pdf version from HERE for around US$50.



What Part Number filter is in the system right now.? That could have a bearing on the bypass valve setting (different springs behind the bypass spool). You should bear in mind that when the oil is cold there is a strong possibility that the filter will bypass on first startup. What oil is in the system as a matter of interest.?

Normally a transmission overhaul/rebuild would call for the installation of 5 new modulating valve assemblies. Do you know if they were replaced in either of the previous overhauls.?

Also do you have any information on whether or not the engine oil cooler, powertrain oil cooler, and transmission pump were replaced after either of the previous failures - or even removed, inspected/cleaned, and refitted.?

 

[Nige]

The powertrain oil filter #25 is mounted on the RH fender.
One magnetic screen #2 is directly in the transmission pump suction line. To access it will require either lifting the cab floor or lowering one of the belly guards.



The transmission suction screen #21 is behind a 4-bolt cover at the bottom of the transmission housing at the rear of the tractor.

 

[ZacharyMartin]

Have an oil sample analysis done and look at the ISO Cleanliness Code numbers would be my first thought. That would give you a clear indication whether or not excessive amounts of particles are circulating in the power train oil system.


The answers to these and lots of other questions are in the Operation & Maintenance Manual. You really need to get hold of one ASAP. Search for Cat Publication reference SEBU7298. If you can't find a used copy on eBay or similar you can download a pdf version from HERE for around US$50.

View attachment 355387

What Part Number filter is in the system right now.? That could have a bearing on the bypass valve setting (different springs behind the bypass spool). You should bear in mind that when the oil is cold there is a strong possibility that the filter will bypass on first startup. What oil is in the system as a matter of interest.?

Normally a transmission overhaul/rebuild would call for the installation of 5 new modulating valve assemblies. Do you know if they were replaced in either of the previous overhauls.?

Also do you have any information on whether or not the engine oil cooler, powertrain oil cooler, and transmission pump were replaced after either of the previous failures - or even removed, inspected/cleaned, and refitted.?

Buying that OMM right now, I've been trying to find it. I'm guessing they didn't replace or check anything they should have, It has a mix match of Chinese modulating valves in it that look like they've been shoved in a vice and hit with a hammer at some point. I had swapped them around to verify my it won't ******* go forward condition. Swapped first and forward and first would just barely grab and slip or not work at all and then forward worked perfectly in 2nd. did the same thing with reverse and just bought a new valve for it as I was running out of useable ones. Then reverse quit working again yesterday after maybe 2-3 hours on a brand new cat modulating valve, I went earlier today and swapped with forward, forward no longer worked and it reversed fine. I took a screw driver and popped the rod that diverts flow free and it worked again.

 

[Nige]

Based on your reply above I think you need to be taking a look inside those two screens sooner rather than later. Brace yourself - what you find may be ugly.

 

[ZacharyMartin]

Based on your reply above I think you need to be taking a look inside those two screens sooner rather than later. Brace yourself - what you find may be ugly.

Assuming those screens are dirty, will cleaning them and replacing the filter be adequate to stop my issue of plugging these modulating valves? Really looking to have a reliable machine for the season to come. Are there any flushing procedures that can be done?

 

[Nige]

Assuming those screens are dirty, will cleaning them and replacing the filter be adequate to stop my issue of plugging these modulating valves?

Not by a long chalk, at least not IMHO.

Take a look at the oil. What type & weight oil is it BTW.?
Does it appear clear & bright or dark and cloudy.?
Does it smell burned.?

I would say that your first step should be to get an oil analysis done to identify the level of contamination in the system. At your local Cat dealer they sell kits that include the necessary to take a sample and also the cost of analysis probably for less than CA$50. It will pay you back 1000 times to know what you have right no. Clean the two screens by all means (take photos of what you find and which screen it came from) but that likely won’t fix the issue.

Your next step should be to look in the filter housing and identify the Part Number of the element that is in there. There have been changes to the P/N that are not reflected in the Parts Manual. You need to be aware of these changes and ensure that the correct filter is installed. See SEPD1230 attached. The element you need is Part Number 343-4465 rather than the 132-8876 that is mentioned in the parts book.

At the same time you need to prove that the plugged filter switch is working correctly. My bet is that it isn’t. While that switch is out make sure that the bypass spool is moving smoothly and that the spring conforms to specifications. Your switch should be installed in place of the Plug #17 in the illustration below. The bypass spool and spring are #15 & 16. The spring should measure 62.5mm long and 15.25mm outside diameter.

 

[Simon C]

If you need a new #164-7577 Filter switch, I have a brand new one still in a never opened sealed bag from OEM Cat for sale on Kijiji, for less than half of the going price. Could save you quite a few bucks.
Simon C

 

[ZacharyMartin]

Not by a long chalk, at least not IMHO.

Take a look at the oil. What type & weight oil is it BTW.?
Does it appear clear & bright or dark and cloudy.?
Does it smell burned.?

I would say that your first step should be to get an oil analysis done to identify the level of contamination in the system. At your local Cat dealer they sell kits that include the necessary to take a sample and also the cost of analysis probably for less than CA$50. It will pay you back 1000 times to know what you have right no. Clean the two screens by all means (take photos of what you find and which screen it came from) but that likely won’t fix the issue.

Your next step should be to look in the filter housing and identify the Part Number of the element that is in there. There have been changes to the P/N that are not reflected in the Parts Manual. You need to be aware of these changes and ensure that the correct filter is installed. See SEPD1230 attached. The element you need is Part Number 343-4465 rather than the 132-8876 that is mentioned in the parts book.

At the same time you need to prove that the plugged filter switch is working correctly. My bet is that it isn’t. While that switch is out make sure that the bypass spool is moving smoothly and that the spring conforms to specifications. Your switch should be installed in place of the Plug #17 in the illustration below. The bypass spool and spring are #15 & 16. The spring should measure 62.5mm long and 15.25mm outside diameter.

The oil has a brown tint and looks like it has some darker material floating in it, didn't smell burnt but it had a weak gear oil scent to it. I've honestly never even seen TDTO so I'm not even sure it has the right fluid in it. I think I'm going to drain all the fluid and take an oil analysis. Check and clean all the screens, check bypass and switch. Throw a new filter in and see if I can flush the powertrain cooler out. I'm debating taking the fluid and running it though a fuel filter with a decently low micron, any idea as to what micron the factory filter is? Thanks

 

[Simon C]

Something like this would be an option, that I have used more than once to flush out slowly an entire hydraulic system. This is a cleaning down to 5 micron in a total synthetic filter with a built in by pass.
I have used also with a needle valve hooked up to pilot pressure with the outlet hose going back into tank with the hose taped up very well with rags to prevent any contamination. Have done this permanently on a Chev 2500 transmission line as in this picture and the particule count that was around 51000 on the genuine Chev filter dropped to 1700 in first 3 hour run.
I had it on till I changed to a 3500, and was happy with results.
Simon C

 

[Nige]

The oil has a brown tint and looks like it has some darker material floating in it, didn't smell burnt but it had a weak gear oil scent to it.

Wanna bet someone has put EP gear oil in it.? Get it our, flush the system and start again fresh with TDTO/TO-4 would be my suggestion.
If it has "material" floating in it that could be an indication that the filter bypass spool is stuck in the bypass position.

I think I'm going to drain all the fluid and take an oil analysis. Check and clean all the screens, check bypass and switch. Throw a new filter in and see if I can flush the powertrain cooler out.

Good plan. Don't forget to use the correct (latest) 343-4465 Part Number of filter.
Please read SEPD1230 (attached above) for the reason why a filter element with a higher micron rating is actually better for system performance. in the srtictest sense of the word the 132-8876 is a hydraulic oil filter, not a powertrain oil filter.

any idea as to what micron the factory filter is?

If it's a 132-8876 - 6 microns. If it's a 343-4465 - 10 microns

 

[Simon C]

Wanna bet someone has put EP gear oil in it.? Get it our, flush the system and start again fresh with TDTO/TO-4 would be my suggestion.
If it has "material" floating in it that could be an indication that the filter bypass spool is stuck in the bypass position.

Good plan. Don't forget to use the correct (latest) 343-4465 Part Number of filter.
Please read SEPD1230 (attached above) for the reason why a filter element with a higher micron rating is actually better for system performance. in the srtictest sense of the word the 132-8876 is a hydraulic oil filter, not a powertrain oil filter.

If it's a 132-8876 - 6 microns. If it's a 343-4465 - 10 microns

If the new Cat filter is that fine then you don't need my filter set-up, but the idea may help you fix some other machine another time. Has gotten me out of some problems.
Because your in Ontario, you could also use the TDTO/TMS all season oil more rated for colder weather in winter, once you have flushed it out as Nige has said, but only after getting some oil samples first.
Simon C

 

[Nige]

Because your in Ontario, you could also use the TDTO/TMS all season oil more rated for colder weather in winter, once you have flushed it out as Nige has said, but only after getting some oil samples first.

You should really get a sample and have it analysed so that you know what's in there at this moment.
Agree with Simon that TDTO-TMS is the best oil for your climate with the wide variations of ambient temperature throughout the year in your neck of the woods - saves changing grades between summer & winter. You don't necessarily have to be wedded to Cat-brand oil. Petro Canada have a couple of perfectly good multigrade TO-4 spec oils.

Petro-Canada PRODURO™ TO-4+ Synthetic All Season | PRODURO | Petro-Canada Lubricants

PRODURO TO-4+ Synthetic All Season provides reliable performance for off-road fleets and ensures the best year-round performance.Read more.

petrocanadalubricants.com

Petro-Canada PRODURO™ TO-4+ XL Synthetic Blend Lo-Temp | PRODURO | Petro-Canada Lubricants

PRODURO TO-4+ XL Synthetic Blend Lo-Temp provides reliable performance for off-road fleets.Read more.

petrocanadalubricants.com

 

[Simon C]

You should really get a sample and have it analysed so that you know what's in there at this moment.
Agree with Simon that TDTO-TMS is the best oil for your climate with the wide variations of ambient temperature thourghout the year in your neck of the woods - saves changing grades between summer & winter. You don't necessarily have to be wedded to Cat-brand oil. Petro Canada have a couple of perfectly good multigrade TO-4 spec oils.

Petro-Canada PRODURO™ TO-4+ Synthetic All Season | PRODURO | Petro-Canada Lubricants

PRODURO TO-4+ Synthetic All Season provides reliable performance for off-road fleets and ensures the best year-round performance.Read more.

petrocanadalubricants.com

Petro-Canada PRODURO™ TO-4+ XL Synthetic Blend Lo-Temp | PRODURO | Petro-Canada Lubricants

PRODURO TO-4+ XL Synthetic Blend Lo-Temp provides reliable performance for off-road fleets.Read more.

petrocanadalubricants.com

Yes the Petro Canada Selection is quite good and is where I buy most of my oils. He needs to get his system cleaned out first, and then quality product behind. It doesn't take too long to get all the oil through a new filter.
Simon C

 

[ZacharyMartin]

Well quite the development. Definitely found my bypassing issue, unsure as to whether or not the filter bypass is functioning properly. Spring seemed fine but I forgot to measure the length, it was already pressing the switch down just by putting it in, and it was caught on the snap ring holding the switch plunger in. Obviously there was some excessive pressure or a sever lack of flow from the filter being plugged. All the o rings sealing it where flat and the filter was the older part number, I'm assuming someone hasn't been doing their maintenance. I found tons of metal of every colour and size, and varying rubber pieces as well. Fluid was ******* dark and has a gear oil smell but definitely not overwhelmingly. I threw the new filter in just so I can float the machine to a yard where I can work on it before half loads hit. I'm going to order a drum of fluid and a couple filters because I'm sure that one will be fucked before it even makes it on the trailer. I'm not aware of the exact flow that causes that bypass switch to activate, but the plunger on the switch was extremely easy to push in with my finger, the spring felt significantly stronger and it depressed the switch as I installed it.

 

[ZacharyMartin]

The bypass plunger and more schmoo

 

[Simon C]

Well quite the development. Definitely found my bypassing issue, unsure as to whether or not the filter bypass is functioning properly. Spring seemed fine but I forgot to measure the length, it was already pressing the switch down just by putting it in, and it was caught on the snap ring holding the switch plunger in. Obviously there was some excessive pressure or a sever lack of flow from the filter being plugged. All the o rings sealing it where flat and the filter was the older part number, I'm assuming someone hasn't been doing their maintenance. I found tons of metal of every colour and size, and varying rubber pieces as well. Fluid was ******* dark and has a gear oil smell but definitely not overwhelmingly. I threw the new filter in just so I can float the machine to a yard where I can work on it before half loads hit. I'm going to order a drum of fluid and a couple filters because I'm sure that one will be fucked before it even makes it on the trailer. I'm not aware of the exact flow that causes that bypass switch to activate, but the plunger on the switch was extremely easy to push in with my finger, the spring felt significantly stronger and it depressed the switch as I installed it.

Think I will let Nige comment on this one. What happened to the inside of the filter. He is going to ask you anyways.
Simon C

 

[ZacharyMartin]

Think I will let Nige comment on this one. What happened to the inside of the filter. He is going to ask you anyways.
Simon C

That's how it was when I pulled it out. Inside was blown apart and there was a dent on the outside where the fluid flows into the filter housing. I don't know if the fluid is way to thick and in the cold it just couldn't flow through, but I'm guessing when I cut it open later tonight I'm going to find it plugged full of debris

 

[Nige]

That oil is disgusting. It might not look like it to you but it’s burnt to a crisp.

Need to see some good photos of what you find inside the filter.

Even though the filter was the wrong Part Number I still reckon the damage to it is another justification for using a multigrade TO-4 oil in the powertrain in your particular climate conditions.

All the metal you found is an indication of what I refer to as a “hard” (metal part or parts) failure - this is not good. A “soft” failure you would see masses of burned up clutch material in the suction screens; something that is generally relatively easy to repair.

My money is on that transmission having to be removed from the machine sooner rather than later.

it was already pressing the switch down just by putting it in, and it was caught on the snap ring holding the switch plunger in.

In case you were not aware the bypass spool has to move AWAY from the switch for the plugged filter light to come on, so the spring pushing the spool hard up against the switch plunger as the switch is screwed into the filter housing is completely normal.

While you had everything apart did you check the operation of the switch.?

I'm not aware of the exact flow that causes that bypass switch to activate,

From memory a differential pressure of 34psi across the filter is what causes the bypass spool to move against the spring force and away from the the switch which sounds the plugged filter warning.

 

[ZacharyMartin]

That oil is disgusting. It might not look like it to you but it’s burnt to a crisp.

Need to see some good photos of what you find inside the filter.

Even though the filter was the wrong Part Number I still reckon the damage to it is another justification for using a multigrade TO-4 oil in the powertrain in your particular climate conditions.

All the metal you found is an indication of what I refer to as a “hard” (metal part or parts) failure - this is not good. A “soft” failure you would see masses of burned up clutch material in the suction screens; something that is generally relatively easy to repair.

My money is on that transmission having to be removed from the machine sooner rather than later.

In case you were not aware the bypass spool has to move AWAY from the switch for the plugged filter light to come on, so the spring pushing the spool hard up against the switch plunger as the switch is screwed into the filter housing is completely normal.

While you had everything apart did you check the operation of the switch.?

From memory a differential pressure of 34psi across the filter is what causes the bypass spool to move against the spring force and away from the the switch which sounds the plugged filter warning.

Yea I had a feeling the fluid was pretty cooked, with it being the old part number and the o rings all being old and flattened I’m assuming it wasn’t changed after the previously torque converter and transmission failure. Definitely indications of major hard part damage that wasn’t in those photos. Quite a few chunks that were much bigger than I’d like to see. Hopefully the friction disks and bearings aren’t destroyed from it going through them. Supposedly there’s only 50 hours on this transmission. But I’m not quite so sure I still believe that. I plan to let the filter I just put in catch some garbage and hopefully not refill the system with contaminated fluid, then change it and test pressure at clutches and do a stall test to see if any slip. I’m assuming even if they don’t there’s been a drastic decrease in the life of all the wear parts in the transmission, I really only need it to do a couple hundred hours so it can cover some payments and hopefully make enough that I can rebuild without sending myself into more debt. Do you think that would be at all possible or just a terrible idea and begging for bigger problems? I know a bigger company would rip that transmission out in a heartbeat but this is really my first big expense and I’ve got a son coming in 3 months so I’d really rather not tear it all down before it makes any money. Opening up the filter now