Bypass Additional Filtration - for a Dual Clutch Transmission?

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Just asking folks the question, per the title of this thread - for reason of preventing metallic "swarf" (metallic wear debris) from collecting on the magnetic (and sensing-) portions of the mechatronic controls... particularly for vw's DQ-250 wet dual clutch automated manual 'box. This apparently has been a problem. If you bypass-filter (using really tight filter media) right from new it seems to me you will not anytime soon build up amounts of magnetic swarf on Mechatronic components and will greatly extend the service life of said transmissions. Comments?
 
Not greatly familiar with the fluid flow of that setup. Does it have cooler lines that exit the unit? If so, it wouldn't be hard to set something like that up. Especially if you use magnets in the filter.

I have a 3 micron full flow filter on my transmission, and the fluid has stayed super clean. Metallic debris tends to corrupt the shift solenoids in my transmission type, so I am glad to have a tight filter and magnets keeping the stuff at bay.
 
Wasp, What brand of filter do you have for the 3 micron full flow? That sounds great!

OP, I don't know if you would need true "bypass" filtration to achieve your goal- maybe one of the metal can Magnefine filters with some additonal neodymium bar magnets around the exterior (or a FilterMag if you've got one). The biggest thing would be to pull as much swarf out of the fluid outside of the case as possible to keep it out of the pump and solenoids, and use the actual filter element of the Magnefine to catch any nonferrous stuff. It's a smart idea to start it as soon as you get the vehicle. Nice idea!
 
I've got a Parker hydraulic filter and filter head. The filter has no bypass valve, but the head does.

I also changed out my transmission's internal spin-on filter from the factory 60-micron spin-on filter, to a Fram XG717. The internal spin-on is a dead ringer for the 7317.

After having to change my solenoid pack once because of solid contamination, I decided that was never going to happen again.
 
As I understand it, on your conventional torque converter automatic trans you have plumbed a 3 micron thru-filter with a filter head that can bypass the filter if the filter becomes plugged or somewhat plugged. Do you know what the bypass pressure is? The reason I ask is 'cause to my way of thinking that could lessen the flow through the A/T cooler (as the filter loads up) and potentially starve one of the lube points that that ATF is flowing to...? It seems to me that 3 micron is very tight media for a flow-through situation. When I refer to a bypass filtration, I mean plumbing an even tighter media filter between the tank-cooler inlet and the tank-cooler outlet lines. A very small % of the normal cooler flow gets filtered at any one time... but if the filter plugs it has absolutely no negative effect on lube flow. You may think that this does not accomplish much ATF filtration - but it really does accomplish an even better ATF cleanup fairly quickly. Yes a minor amount of ATF cooling is lost with this bypass action... but often adding this bypass filtration is done at the same time a person adds an aux trans cooler in front of the rad.
 
The DQ250. Does not appear to have any cooler lines
The HEX is right atop the transaxle...

Screenshot_2018-10-05-22-31-50-1.webp
 
Last edited:
Originally Posted by Cdn17Sport6MT
As I understand it, on your conventional torque converter automatic trans you have plumbed a 3 micron thru-filter with a filter head that can bypass the filter if the filter becomes plugged or somewhat plugged. Do you know what the bypass pressure is? The reason I ask is 'cause to my way of thinking that could lessen the flow through the A/T cooler (as the filter loads up) and potentially starve one of the lube points that that ATF is flowing to...? It seems to me that 3 micron is very tight media for a flow-through situation. When I refer to a bypass filtration, I mean plumbing an even tighter media filter between the tank-cooler inlet and the tank-cooler outlet lines. A very small % of the normal cooler flow gets filtered at any one time... but if the filter plugs it has absolutely no negative effect on lube flow. You may think that this does not accomplish much ATF filtration - but it really does accomplish an even better ATF cleanup fairly quickly. Yes a minor amount of ATF cooling is lost with this bypass action... but often adding this bypass filtration is done at the same time a person adds an aux trans cooler in front of the rad.


The filter I am using is rated for something like a 70 GPM hydraulic system. I had to install fittings to step down the ports from a little over an inch, down to the half inch my system needed. My transmission would pretty much have to self-destruct on its own in order to plug this filter a good amount. I've since installed a pressure differential gauge by taking advantage of 2 of the four 1/8"NPT ports on the filter head, and can confirm that 20k miles of driving has yet to have any effect on this filter. It is ridiculously oversized for its application. The third port gives me converter outlet temperature, which is a lot more important than fluid bulk temperature is.

Bypass filtration absolutely works. I know enough Ford Super Duty owners who have gone to change out their OEM NTZ bypass filters to know that. Same situation every time. Filter is black as pitch, fluid is clear and cherry red.

I'm still considering using a toilet paper bypass filter in order to get that nice sub-micron clean out of it, but that will be later. No real need right now.
 
Originally Posted by DoubleWasp


The filter I am using is rated for something like a 70 GPM hydraulic system. I had to install fittings to step down the ports from a little over an inch, down to the half inch my system needed. My transmission would pretty much have to self-destruct on its own in order to plug this filter a good amount. I've since installed a pressure differential gauge by taking advantage of 2 of the four 1/8"NPT ports on the filter head, and can confirm that 20k miles of driving has yet to have any effect on this filter. It is ridiculously oversized for its application. The third port gives me converter outlet temperature, which is a lot more important than fluid bulk temperature is.

Bypass filtration absolutely works. I know enough Ford Super Duty owners who have gone to change out their OEM NTZ bypass filters to know that. Same situation every time. Filter is black as pitch, fluid is clear and cherry red.

I'm still considering using a toilet paper bypass filter in order to get that nice sub-micron clean out of it, but that will be later. No real need right now.


Doublewasp - it sounds like you have addressed this well with your mega-capacity through filter + all of the additional safeguards you have added. BTW, i have an NTZ toilet paper filter (housing + filter) - but have not yet added it to my Honda, operated in bypass fashion. Interesting feedback you provide re the Ford Superduty transmissions with cartridge style bypass filters. Encouraging...

One challenge folks may face in plumbing one in to the transmission cooling lines is how to "bead" or create a bulge in the cut lines. If they are Imperial size, just use a compression fitting, remove the hex collar, then use acid paste and lead-tin solder the brass ferule onto the cad plated line. If metric, then get a metric compression ftg and do the same? They also could use a Parker beading machine.
 
Ford didn't contract NTZ because they are a joke. That's real tech right there. And no exaggeration on the filter condition, either. Just look it up. Many people would frequently think there was something wrong with their transmissions because those filters just come out black after 10k miles.
 
Weird. You know? Months ago, I was trying to get information on the "toilet paper" style filter and filter housing that comes from the factory in my dirt bike.

It has M10x1 ports on both sides, and sure looks a whole heck of a lot like that! The little toilet paper filter on the inside looks just like an NTZ roll, and I'm pretty sure dimensions match! You may have just solved a mystery for me. I think I'll order one and compare. There's a decent amount of people who would be excited to know.

https://bobistheoilguy.com/forums/ubbthreads.php/topics/4335720/KTM_LC4_Toilet_Paper_Filter
 
Make darned sure you order the "banjo" X barbed fittings (plus the two copper or aluminum flat-gaskets) for each end of the unit and be sure to bead any tubing you connect to. For the classiest arrangement use Oettinger (sp?) or Oetker (sp?) twin-ear crimp-type hose clamps rather than worm gear clamps. Or use fuel injection style rolled-edge band clamps, or gear clamps that have a sheet metal backing behind the worm gear. The Oettinger's are in my mind the classiest.
 
Oh, and selection of good, durable, long lasting hose is of paramount importance, routed so as to be impossible to sustain a snag or other mechanical damage. I'll get off my soap box now, LOL ☺.
 
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