When adding an inline filter in the cooler circuit, should the rock catcher be left in place or can the foam be removed which would completely eliminate the need to drop the trans pan if it has a drain bolt? I know the filtering wouldn’t be done on the way to where it’s going as it does in an engine, but if there’s a filter in the pan you’d still have to take it off every so often, right or am I overthinking this
Deleting pan filter in favour of inline on cooler circuit
- Thread starter Lockasiam
- Start date
dnewton3
Staff member
What would be the harm in leaving the "rock catcher" in its proper location and adding the inline filter? Most of them are considered "lifetime" filters anyway.
I don't understand why it's a mutually exclusive proposition to you. Why not both, rather than either-or?
I don't understand why it's a mutually exclusive proposition to you. Why not both, rather than either-or?
Removal of the service item in the transmission would mean no need to drop the pan ever
dnewton3
Staff member
Most of them are considered lifetime anyway; no need to drop the pan just to service filter.
BrendanC
$100 site donor 2024
rock catcher is there to prevent large debris from entering the pump. i think it’s a good thing to leave in place even with a filter in the cooler circuit. it will hopefully prevent the pan filter from loading but i would still change it on a 50-60k interval. i change my cooler line circuit filter once a year.
4WD
$50 site donor 2025
I added a cooler, spin on filter, and drain plug to a GMC after changing the pan filter - then never changed the pan filter for 77k …
BrendanC
$100 site donor 2024
it would be just fine, but if you can shove a xg8a. sized filter in i would reccomend that. more media for a higher flow rate/holding capacity.
Please be more specific about the application. Most pan filters double as an oil pickup, why in the world would you consider getting rid of something like that? Also, if you're doubling up the filtering it should pretty much eliminate any need to replace the rock catcher aside from a catastrophic failure of some sort.
@‘53 Stude sent me like 6 of the 16 size filters so I’m gonna be using those for a while
Fair enough
Except that the filter is also the pickup on many transmissions.
Remove it and destroy the trans because now the pickup is an orifice located much higher up relative to the fluid, and the pump will suck air.
Look at this, for example, from a Chrysler/Mercedes transmision
You are trying to solve a problem that doesn’t really exist - you want to improve filtration? Sure, go ahead, add your in line external filter, but the factory filter is not a negative. It isn’t a “problem” that was left there for you to solve. For example, the million mile Tundras have run just fine with the “rock catcher”, so don’t go trying to fix something that doesn’t need fixing.
This and @Tman220 post.
Not removing the whole pickup, that’s stupid. Removing the foam from inside but I guess not
Removing the foam or paper would likely tear it, leaving bits of glue and foam to get sucked in and destroy the transmission.
Just leave the filter in place. Drop the pan, put in a new one and you’re all set.
If it helps, my wife’s 2002 Volvo has 308,000 miles on the original transmission filter. It is not externally replaceable. So, I added an external filter.
But the original one at 308,000 miles is still in there, untouched.
I have added an external filter, cooler, and thermostat to each of the automatic Volvos. All tucked up underneath the bumper cover. Some pictures on this site on the 2002 V70 T5.
https://www.volvoxc.com/forums/showthread.php?27334-02-XC70-Transmission-Flush-From-Bottom
A discussion on the 2001 V70 with pictures of the same set up in this thread.
So, I am in favor of adding the external cooler, filter, and, in my recommendation, thermostat, but leave the factory filter alone.
To get the foam out you end up destroying the filter case, it's a plastic welded seam, there is no way to put it back together.
dnewton3
Staff member
No, no, no ....
Let him rip the OE filter apart; tearing at the welded plastic or trying to uncrimp the metal seams.
Then after he cracks that clam open, he can pick apart the innards; leaving little bits to float into the valve body.
Then try to reseal the parting line joint(s); maybe some globs of RTV will help?
Afterward, he can come back and tell us how great his experiment was ...
Photos or it didn't happen!
Let him rip the OE filter apart; tearing at the welded plastic or trying to uncrimp the metal seams.
Then after he cracks that clam open, he can pick apart the innards; leaving little bits to float into the valve body.
Then try to reseal the parting line joint(s); maybe some globs of RTV will help?
Afterward, he can come back and tell us how great his experiment was ...
Photos or it didn't happen!
NO. Don't add an inline filter. One more leak point. It doesn't have the capacity. When it's time to service the transmission (35-40k miles) do it the correct way and drop the pan and replace the filter. And use an OEM filter. Too many aftermarket filters are crap. Spoken from experience from many clients.
Don't try to reinvent the wheel.
There isn't "foam" inside of any filter. The material is Dacron.
