Transmission Remote Filter and Fluid Analysis

[mikeyanxu]

Vehicle: 2019 Expedition max XLT.

Transmission: 10R80

ATF: Motorcraft ULV

Couple of weeks ago, on 7/20, I installed a remote hydraulic filter to the ATF oil cooling line, in series with the heat exchanger. The filter (wix 51269) is 10 micron nominal with a 50% efficiency for 5 micron particles and 95% for 17 micron particles. The modification was done at 5800 miles and I took fluid sample right before the modification just wanted to know the baseline.

The fluid analysis result came couple of days later. The results shocked me in terms of how many particles it has. The initial fill ATF only had 5800 miles when the sample was taken and the cleanliness was bad, very bad. 23/21/12. It seems they made a typo on the metal. It should be iron and copper instead of iron and chrome.

The result is bad enough to cause big panic if it is for my work (aerospace). Evidently, the OEM filter in the pan seems to be very coarse. It makes sense, because it is a pump suction filter. In hydraulic industry, there are no filters on the pump inlet due to cavitation concern. Ford probably just have a coarse filter with a large filter arear on the pump. It is more like a filter for large foreign objects to prevent catastrophic failures.

If you like to learn more, research on ISO4406 standards. Or NAS1608 standards. I can explain a little: For a hydraulic system, the cleaner the fluid, the longer components last and the less chance to have unplanned maintenance. The higher precision and pressure the components are (fuel components, servo valves, high pressure pumps), the cleaner the fluid has to be. For example: (ISO 4406) 18/16/13 is required for diesel fuel. 16/14/11 is required for servo valves. I guess those solenoid valves inside of the transmission are just 4 way or 3 way valves (Also called bang-bang valves), still, those require minimum 19/17/14 for fluid cleanliness. I guess only ford knows that number. I am sure ford knows how much less money they will make if every transmission has a pressure or return filter…

Yesterday, 8/4, I drew another sample, the filter has been in the system for roughly 700 miles. I will keep everyone posted.

 

[Uturn]

I understand where you are coming from, but before putting some people in a panic there are a couple of things that need to be considered. First, this is not a aerospace hydraulic system or even the type of system you would find in a typical machinery application where a hydraulic pump is used to power a hydraulic motor or ram. In this system the pressure is used to activate six clutch packs which contain components that wear with every shift. The byproducts of that wear end up in the fluid along with the normal wear of the planetary gears and pump components themselves. It could be the material in the clutch plates themselves make up the majority of the particulate matter in the analysis. As far as the factory filter, I could not find the specifics for particle size and efficiency, only this from the manufacturer.

"It’s also engineered (fluid) to last the lifetime of the transmission, aided by a new filter that has two levels of high-efficiency media and a pleated design with much greater surface area than the filters used in the current six-speed transmission."

I do agree on the cleanliness of the fluid in regards to transmission life and that the fluid should be changed on a regular basis. I also agree that adding another filter is not a bad idea unless it interferes with the flow. This transmission does use a variable flow pump for fuel economy sake and I do not know if it is metered for flow or it controlled by programming and if that programming would take into account the additional restriction of a filter.

That said, I do appreciate the time, ingenuity, and effort you put forth in the system and the willingness to keep everyone apprised of the outcome.

 

[16plati]

@mikeyanxu your truck probably has excess particulate from the transmission break in period where increased particulates are expected. How much did you pay for this aerospace device?

 

[mikeyanxu]

Thanks gentlemen.
Sorry I didn't intend to make anybody panic. Fluid analysis is like blood test. The two cheese burgers and beer from last night dinner will show on the test result.

The hydraulic side of the gearbox has a vane pump, a dozen or more solenoid valves, and a lot more (check, counterbalance, etc) valves, highly integrated into sandwiched valve bodies. Those are the parts I can see between the shop manual and teardown video. The cleanliness level is bad, period. It is maxed out on the table. I just don't know the limit from Ford. If I know the micron level of the OEM filter, I would be a little less concerned. My guesstimate is close to 100 microns.

Yes, it is from the break in period and the internal filter cannot maintain the cleanliness. The next analysis report will show how much difference the remote filter makes.

I paid for less than 300 bucks including the ford oem hose assembly (100), derale filter head (60), and hose kit (80). The spin-on filter is couple of bucks. The OEM hoses are just for in case. The darn ford factory tubes have flat spots on the bends. Shame.... I have bent tubes better than that in my garage.

I have the adele clamps, clip nuts, and sleeves from previous projects. I had to fabricate a bracket to provide a piont to attach the two hoses with two adels. Welded a plate to the running board bracket and attached the filter head there.

Regarding the restriction and so on. I have calculated the pressure drop. Those tubes and hoses are 1/2". For 3 feet of length, the pressure drop is 8 PSI at -40F and almost 0 at 100F. I used the standard hydraulic fluid viscousity and ULV is thinner. The filter element itself has almost no pressure drop and it is for 10 GPM. I doubt the transmission flows that much. A transmission paired with a diesel can flow beyong 10 GPM at high RPM. A vane pump will continue to pump until something breaks. It is non-compensated.

I do notice the variable flow rate. The filter has very slight vibration from fluid pulsing at approx. 1500 RPM when fluid is at the operating temp. This happens during shifting. That is when the torque converter and pump changes flow rate. The vibration is sent from the bracket to the foot well area. Remember the filter is attached to the running board bracket? The bracket is attached to the cab, not the frame. I am looking for a solution to mount the filter to the transmission or the frame so I won't feel the vibration through the cab.

 

[ROBERT BONNER]

Excellent work and report out. I just came across this thread. It's been 3 years, do you have any relative updates? I have a '20 with 35K on it and I'm ready to drop trans fluid, change filter and upgrade to a pan with a plug. It's the right time for me to add a pressure side filter.