CLOGGED transmission filter

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Has anybody ever seen a clogged transmission filter?

It is my understanding that the tran filter only prevents LARGE materials from getting into the transmission, so wondering if anybody has seen a clogged at filter?
 
I've only ever seen dirty transmission filters, typically the media has started out yellow and turned the brown/red tint of ATF. Completely disassembled the filter from my stratus after 110,000 mile run and only found small specs, almost everything that could possibly cause any kind of clog was on the magnet.
 
Don't think it would be possible, being that the magnet simply sits at the bottom of the pan. I don't know exactly how the atf gets "filtered" but for example, in an engine, ALL oil within the engine must pass through the filter, that may not be the case with the ATF?

Granted, it's still something you want to "maintain" on a schedule...but I can't see it completely clogging. If anything it will just keep making a bigger, taller, and wider "pile" of shavings.....

But could depend how deep the pan is, where the filter is located, etc....too probably.
 
I've seen one, but that was over 30 years ago.

Powerglide trans with over 100,000 on it.

Every once in a while the trans. would lock up and car not move.
Changed the fluid and filter and it never happened again.

GM uses an actual filter media. Some just have a screen that catches the big chunks.
 
It will never happen unless water gets in the tranny. The glue holding the clutch material together is water soluble. The 45RFE and 545RFE have a normal flat filter plus a spin on cooler return line filter. It's an actual filter sans the ADBV.
 
Seen MANY clogged trans filters. Did trans work at dealers for a long time. If you truly have a clogged trans filter, a "service" will do you no good. By the time there is enough clutch material/metal to CLOG a filter, the unit is toast.

For years we had torque converter lock up clutches that would fail, flooding the unit with material and metal. Result was clogged filter, low fluid pressure to the other clutches and bands, resulting in more clutch material.
 
the tranny filter on my fairmont is, i believe, completely useless. i bought the new one, and saw its nothing more then a piece of window screen mounted in a little metal housing. the "media" part was literally as wide open as a window screen. i took the old one out and it looked as good as new.
 
If there is enough clutch material to clog a filter a rebuild is in order. It takes a whole lot to clog a tranny filter and I have only seen that in complete fails.
 
Yeah, the only time you see a clogged filter is after a major failure. But the thing is, you don't know what the "chicken" was. If, in the course of normal operation, the filter partly clogs and restricts flow, the trans could begin to slip. Just a little at first but it would then start dropping more debris, which would then get caught in the filter, further restricting flow and... well you see where I'm going here. It would be difficult to discover the root cause.

The thing is.... according to the decades of work Eleftherakis and Khalil did studying AT filtration (which you can get at the SAE store)... the average range of sizes for "normal" wear debris in an automatic is 5-15u. That stuff will pass right thru even the best 60-80u pan filters that are out there now, never mind the 100-150-200u screens of the old days.

I think it might be possible to clog a 60u filter with oxidative byproducts from excessive heat but I suspect the trans would fail in some other way before teh filter would cause it to fail.

Excessive amount of that size contamination will beget more and more debris, more and more wear and it will eventually kill the trans. By the time the big stuff comes along to clog the filter, the trans is already severely enough damaged that its on borrowed time anyway.

So, and y'all can check my logic here because this thought just occurred to me, it seems that it really isn't possible to plug an in-pan trans filter in normal circumstances, without some other major failure taking place first. I can invent some scenarios where it might be remotely possible, but the vast majority of the time, I don't think it would.

From my reading, and a coupla great conversations with Abe Khalil, it seems prudent to change the filter and clean the magnet in the pan short after break-in is achieved, because the trans generates 75 percent of it's lifetime of normal wear materials within the first 5K miles. That comes from break in as well as the contaminants that're built in during manufacturing. After that, it would seem safe to me the let the pan go... at least over a couple of OCIs, if not the remainder of the transmission's lifetime. Without knowing for sure, I would probably change it just for observation and learning reasons but my semi-WAG now would be that it basically can't clog without other things happening first.
 
My father had given me a 66 Ford Falcon which had over 100K on it, and he never serviced the transmission. One day I went out with it, shifted it into D and all it did was rev. I dropped the trans pan and it was covered in junk and some metal filings. I replaced it and it was fine. I started maintaining cars for my father from that point on.
 
Originally Posted By: Jim Allen
Yeah, the only time you see a clogged filter is after a major failure. But the thing is, you don't know what the "chicken" was. If, in the course of normal operation, the filter partly clogs and restricts flow, the trans could begin to slip. Just a little at first but it would then start dropping more debris, which would then get caught in the filter, further restricting flow and... well you see where I'm going here. It would be difficult to discover the root cause.



This. I picked up a 91 cutlass ciera (4t60, 3300) for my BIL. The vacuum modulator may have been malfunctioning, not giving enough pressure to the clutch packs under load, and the higher gears slipped. Anyway I dropped the pan and found an above average collection of gray dust. Stuck an adjustable modulator on there (red stripe, ten bucks!), changed the filter and fluid, and everything came back to life!

This was a shotgun approach and I agree on the voodoo of knowing what went out first, or even if my higher line pressure (I didn't pressure gauge test any ports or anything) is a band aid for a tired box.
 
The only one i ever saw totally clogged was an 1970 Chevy PU TH350.
The unit didn't work in any gear, before swapping it i changed the filter and it worked like new again.
The unit continued to work fine another 10 yrs when the truck was finally scrapped.
 
Thanks for all the great replies


Reason I asked was I have been extracting and replacing the ATF on a GM 4t60e over the course of 3 weeks. I have put in about 8 quarts of new after extracting the old a few. Quarts at a time. This car has 106k. I have no idea if the at was ever serviced. It was owned by an older woman to about 70k. Then my family member took it. I know my family member never serviced the at I do not know what the older woman did but I think she was a bring to dealer on schedule type.

There are no problems with this AT. I was being proactive in changing the fluid. The first couple quarts I took out where very dark-- could not see through it at all after in disposal container. It did not smell burnt in any way just appeared dirty. I didn't expect that as when I would check the dipstick before changing any of the fluid it would still have a pinkish brown color on the cloth.

Anyway I have a new filter ready to go but I'm wondering if I can just drive it the way it is now without changing the filter/ dropping/cleaning the pan. Or. If I have to get a new filter in there very soon.


Since changing ONLY The fluid I haven't noticed any changes at all..... Drives nice and smooth the way a " rolling couch " old man car should

Thanks
 
Knew a girl in college who had a tempo or some other POS and she said that after driving for a while the car wouldn't go when she hit the gas. She would turn the car off and let it sit 10 min. She said it got diagnosis as the tranny. Figure the filter was getting clogged.
 
No lie! I used to change my tranny filter in my '73 Chrysler NewPort(Torqueflite 727 3 spd.) every 2-3 years bacause it would clog often. It was a very efficient filter in trapping debris as the tranny would start to slip otherwise.
 
Interesting anecdotes but, thus far, all the examples I see are old school automatics, which are much more tolerant of abuse and contamination. Would a modern electronic trans be able withstand the amount of contamination flowing through it without a failure... before the filter clogs.
 
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