Tranny Filter

[Joe_Black]

Joe,
Can you explain a little bit more what you mean about an inline filter possibly damaging the tranny? I was thinking about getting one, but don't want to do anything that might be harmful. ACDelco claims their filter "maintains proper fluid flow" and even has a safety bypass valve "to maintain coninuous flow" in the event filter blockage occurs:

On most automatic transmisssions, especially so on the 4L30E, the fluid is circulated to the cooler via a low-pressure output from the valve body of the transmission. Its design parameters cover just moving the fluid through unrestricted lines and the transmission already has a filter designed to 400% of necessary capacity. For an aftermarket filter to go into bypass mode a certain line pressure has to be reached, usually between 30 and 50 psi depending on the filter and system. At those pressures the valve body will have pretty much found somewhere less desireable to pump the fluid internally.

The return from the tranny cooler just dumps back into the pan where the fluid is suctioned through the filter. Again, the source wasn't designed with enough pressure to push fluid through filter media. It can, for a time, but it won't like it.

If you look at professional and motorsports transmission filter setups there's always an outboard pump to move the fluid through the filter media and any additional or specially mounted coolers. That outboard pump picks up from the valve body output and boosts it to the necessary pressure to get through whatever additional plumbing is in the system.

Hope that helps explain my opinion.

[Tone]

Sure SOME inline filters can do what you describe but if you will investigate the one I recommend (and have used on the VX and the ML) http://epntz-filter.com/sect1b.asp with incredible cleanup results (I'll post results soon from a 30 day before and after test)! All of the fluid is not forced through the filter but rather a percentage is bypasses each time - it takes many passes to clean the fluid and in the event of a blockage, has a failsafe bypass. PPNTZ designed this filter for Ford and cut their tranny failures by over 40%.

The fluid to the cooler IS under reasonable pressure and not just suction from the pump as evidenced by cutting the line to install the filter and turning over the motor just a click and over 8oz of fluid comes shoolting out. Everything I recommend here I USE first BEFORE talking about it. If it doesn't work for me, I can't really suggest if for someone else.

4L30E tranny pressures are much higher than you state Joe, running as high as 150psi during hard shifts - put a guage on the fitting on the driver's side of the tranny. 4 micron debris vs 80micron debris floating around and through the transmission - which is better for it? Or maybe all these inline filter manufacturer's are in cahoots with the tranny manufacture's to cause early failures.....

[Joe_Black]

4L30E tranny pressures are much higher than you state Joe, running as high as 150psi during hard shifts - put a guage on the fitting on the driver's side of the tranny.

I'd like to do that to compare to the service manual specs. Please detail how you were able to plumb such a gauge, monitor and log its pressure trends during operation.