External transmission filter retrofit kit

[Dr_Snooz]

One of the jobs I really detest is changing my transmission fluid. Rolling around under the truck, dumping oil all over myself and the driveway, etc. is something I'd be just as happy avoiding.

So, I got one of these for the work truck...


(https://www.summitracing.com/parts/der-13090/overview/)

...along with a new trans pan with a drain bolt. I'm hoping to turn this nasty job into something more akin to an engine oil change, rather than a hazmat situation. I'll be using a Wix filter that filters cleaner than the pan filter, so there shouldn't be any need to change the internal filter after this.

I like the idea enough that I'm considering doing it on all my trucks. Does anyone have any experience with these? Any wisdom they'd like to share? Thanks!

[Stewart G Griffin]

Interesting.  i glad you brought this up because i'm getting ready to change my fluid, but i'm waiting on the right filter to be delivered.  However, if this works, i may consider it.

One question i do have is do you still have to run the stock filter for pressure reasons?   Such as on a TH-350?

If you use a Fumoto valve in the pan, the fluid change will be even faster:
http://www.fumotousa.com/

[VileZambonie]

Being an auxiliary filter, it is an additional filter but does not eliminate the fact that you still have a filter inside the unit that needs to be serviced so I am not sure this will fully accomplish what you are trying to do. In fact it adds one more service point and additional points of potential messes.

If you are running a pan with a drain plug you should have no issue dropping the pan without making a mess. Consider upgrading to a high quality reusable gasket that allows the pan to separate easily from the case and use a large catch pan.  If you are doing it on your back, jack up the front of the truck and lower the rear portion of the pan first.

[FlatBlack77]

that filter is going to be on the out line that goes to the cooler. so the fluid has to be drawn up through the internal filter into the transmission then out of the trans to the filter to the cooler then back in. unless you can eliminate the factory filter, you will be filtering filtered trans fluid

[bd]

I agree with Vile and FlatBlack.  All fluid is drawn through the factory pan filter, but only a portion of the fluid passes through the external oil cooler as the fluid returns from the torque converter.  An auxiliary filter installed in the inlet line to the cooler will help keep the cooler clean, but will not filter all of the fluid passing through the transmission.  I've incorporated this modification on my 700R4 just to keep the coolers free of debris.  A sand cast aluminum oil pan with a drain plug and reusable gasket is a good way to minimize mess during service and prevent leaks between service intervals.  Adding an auxiliary filter just makes for one more filter to change.

[Dr_Snooz]

I'm not so sure guys. Blackstone Lab results don't lie.

https://m.youtube.com/watch?v=HzQE9110tmg

[bd]

No argument against decreasing contaminants.  The main idea we were trying to convey is that the primary pan filter will still need to be serviced and that the auxiliary filter is a bypass filter that won't strain 100% of the fluid distributed through the transmission.  In other words it doesn't preclude servicing the factory filter.  You will still incur replacement of the factory filter and cleaning the oil pan.

[Dr_Snooz]

It's a fair point and I wasn't expecting that I would NEVER remove the pan again. I'll probably pull the pan after a few fluid changes, if only from curiosity. A more important question is, how long could one go before having to do so? My bet is that with regular fluid changes, replacements of the external filter and periodic Blackstone analyses, you could go a fair while. I'm definitely sold on a good rubber gasket though. I hate scraping cork.

[bd]

Well, recognizing the fact that the fluid is filtered by the factory pan filter BEFORE flowing through the bypass filter should provide some insight.  No?  The fluid flowing through the bypass filter is "pre-filterd" by the factory filter.  Hence, one might expect the bypass filter to enjoy the extended service life over the factory filter - although the auxiliary filter may remove finer particles from the fluid, depending on whose filter you use.

[Stewart G Griffin]

i'm not real clear on this----if the engine is running and thus the trans is also turning, then the all fluid from the converter and for that matter all the fluid from anywhere in the transmission WILL eventually pass thru the cooler in around 30-45 secs?

If true, then why do we need to run the stock filter?

[bd]

...all the fluid from anywhere in the transmission WILL eventually pass thru the cooler in around 30-45 secs?

If true, then why do we need to run the stock filter?

Where did you come up with this datum, Stewart?  What do you propose to use in lieu of the stock filter?  Look at the attached, simplified block diagram.  An external filter (red) plumbed into the cooler line is a "bypass filter."  If there is no primary filter to process 100% of the fluid flow, what will prevent the unfiltered portion of fluid (blue) from distributing abrasive particles into the valve body and throughout the transmission?  Why would you eliminate the transmission's primary means of fluid filtering only to accelerate seal wear and jam lap-fit spool valves?  Do you get the idea?



A fine filtration auxiliary filter can augment a factory pan filter, but not replace it entirely on an otherwise stock transmission configuration.

[Dr_Snooz]

Given that your pan filter also acts as the oil pickup, I wouldn't remove it entirely. The external filter with a Wix 51269 is a fine filter and will pick up a lot that the pan filter lets by. FWIW, I've seen numerous Honda transmissions with over 300k miles on them. The trans' are sealed units with nothing more than a non-serviceable fine screen to filter the fluid for all those 300k miles. It works well enough obviously. When you rebuild them, the screens are not clogged, nor is there a lot of stuff to remove from them. Most of the debris in the unit is a fine metallic paste that the average GM pan filter wouldn't screen out anyway. The magnet in the pan would do a better job, which is why it's there, I imagine. The GM pan filter is a relatively large 20 micron filter and is going to let a lot of stuff go right by.

Without getting too worked up about it... I'd be curious to know what would happen if you replaced fluid regularly, but ignored the pan filter. What would happen? Would it clog up and restrict flow, or rupture and stop filtering altogether? I'll admit that I wouldn't want 20 micron steel particles flowing freely through my trans, but then, how did they land in the pan if they weren't already flowing freely?

[bd]

Gravity!

[VileZambonie]

Think of it like this guys, stick a straw in a fish tank and drink the water, install a diaper on your lower end to filter the water. Still thirsty?  An auxiliary filter is just that, an auxiliary filter. It doesn't hurt but does not eliminate the need for the pick-up filter.

As far as comparing the Honda unit you are referring to to a clutch type planetary based transmission, they are very different. Think of the Honda unit you are speaking of as being more comparable to a manual transmission that is operated automatically and uses a torque converter. Apples to Oranges

[Stewart G Griffin]

i think i get it now, but ALL the fluid will eventually pass through the external filter in under a minute?