Magnefine Cures Shifting Problem

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Have an '08 Chevy Uplander as a work schlepper. It has the 4T65E transaxle in one of it's final applications. It is somewhat notorious for a condition called "slip and bump," whereby one of the mainline solenoids is slow to respond and on acceleration from a stop the trans slips for a second due to low pressure, then hooks up with a bump... the severity of which is relative to throttle application. Obviously, the long term effect of this is a tranny job. The cure, if the trans is otherwise in good shape, is to replace a particular solenoid before the trans is damaged. There are a couple of other problems that could cause this symptom, but the solenoid is one of the most common.

Needless to say, my old schlepper started this behavior. Yes, I have maintained the fluid and it has about 15K on a change to the correct Dex VI oil and a new Filtran pan filter. Intended to add a Magnefine at service time but it's a tight engine compartment and I was busy and lazy. Never got the round to it!

Changing the solenoid is a fairly onerous project, involving removing most of the suspension from the driver side, loosening the subframe and hanging the powertrain assembly down for access to the side cover, under which is the valve body and solenoids.

Further research showed that it wasn't always or often a solenoid failure, but iron particles partly jamming the solenoids. According to John Eleftherakis and Abe Khalil, who have done a series of ATF studies for the OE trans manufacturers and the aftermarket starting in the late '80s, approximately 90 percent of the contamination in a trans is metallic; 51 percent of that being ferrous (iron/steel), 21 percent copper, 11 percent aluminum and 7 percent lead. The particles range in size from 5 to 80 microns, about 82 percent of them larger than 5 microns. Obviously the exact mix is going to vary but it's clear that much of it is iron and that a pan filter at 80 um is going to let a LOT of it pass.

So, what is a solenoid? An electromagnet! Over time, it attracts ferrous particles. If enough attaches, it can begin to cause trouble.

The GM community has discussed this problem at length and because it's a very common inter/platform gearbox. There was a LOT to wade through. One of the consistent themes was to add more powerful neodymium magnets to the pan internally, both as a cure and as a prophelactic. Well, hey, I had a Magnefine ready to go! Might as well try the easy cure first.

As most of you know the Magnefine consists of a 30 um filter and a very large magnet, past which all the cooler line flow has to pass. Now, 30 um filration is not the most whizbang number by itself, but if you consider the magnet will catch 95% of the ALL the iron, regardless of size, (a number given to me years back by Magnefine and one I have little cause to doubt), and since iron is half the overall metallic contaminant, then it does pretty well indeed.

Found a place to install the Magnefine, cut and flared the cooler line, and installed it. This was about three months back. I noted the problem about three times the first time I drove it and it hasn't happened since. Three months and about 3K miles later, it hasn't happened again so I am provisionally declaring the problem cured. If it desn't happe for a year, I'll call "CURE!" out to the heavens and thank the transmission gods for bestowing a favor upon me.
 
Glad to hear that this has worked for you!

I have an 05 Impala that had the same issues. I had the same thought as you, though I was not confident enough to cut the line and install the Magnefine filter. So I dropped the pan, installed extra magnets in the bottom and on the new filter, as well as installed a TransGo Shift kit. Coming up on a year later and haven't experienced the symptoms since. One of these days though, I like to get a Magnefine filter installed.
 
GM issued a bulletin in 2012 regarding this issue. As you mentioned, the "fix" was simply to add more magnets to the pan.


 
Thanks for posting that GM info! I had not seen that. Next time I drop the pan, I'll add a magnet too. Have several from old Magnefines and they are suitable. It's really a pretty good gearbox overall but you can kill it quickly letting it slip and bump too long.
 
Many transmissions now have an array of magnets. The last one I worked on had 9 large ones firmly gripping the pan. That's quite a bit of capacity -- significantly more than the filter.

It's not very likely that you can reverse the ferrous buildup on the solenoid. The whole problem is that the particles are tenaciously holding onto their new home.
 
Originally Posted By: djb
Many transmissions now have an array of magnets. The last one I worked on had 9 large ones firmly gripping the pan. That's quite a bit of capacity -- significantly more than the filter.

It's not very likely that you can reverse the ferrous buildup on the solenoid. The whole problem is that the particles are tenaciously holding onto their new home.


Maybe, but how do you account for the sudden cessation of symptoms? Both for me and others? Also, bear in mind that this particular tranny has a notoriously wimpy OE magnet. I can only assume that at least some of the buildup drops off when the solenoid is de-magnetized. Anyway, it was a dramatic change and I don't take note of things that aren't.

Also, the Magnefine places the magnet right into cooler line flow, so it's going to do a significantly better job of grabbing particles than something laying in the pan. On one of my other rigs, I had an idea of cooler flow and estimated how long it would take to filter all the oil thru. If you do a search of some of my older posts, you can find some particle analysis done on some of my tranny oils before and after the Magnefines. I'll your finger do the pecking if you are interested enough :) < ).
 
I've run Magnefine transmission in-line filter on several of my older cars and now on my Optima SX (since ~8K miles). I believe they do an excellent job and highly recommend them. There is a new more robust design out from them now as well.

Adding an external trans cooler (B&M) if one is not already on the truck/car would be well worth the effort as well as adding the filter IMHO.
 
Jim,

For automatic transmission fluid, I have Magnefine filters on some of my work trucks and I also have inline filter mounts with regular engine oil filters and external magnets attached to the sides on other trucks. I swap out the Magnafine filters around 15,000 to 20,000 miles and open them up. The magnets have a slight coating of extremely fine paste and not much else on the paper filter. I do get good service life from my transmissions and when it comes time for them to be rebuilt, only clutch plates are worn.
 
So, these two GM magnets would just be placed on the outside of the pan, in the proper locations?

I'm confused, as it says to not remove the transmission oil pan, unless necessary for other reasons... and it shows the time as .3 hours (18 minutes).
 
The magnets go inside of the pan. The one in the top left of the illustration goes on the filter and the other goes on the pan itself. The new magnets are substantial stronger than the square magnet installed at the factory.

With regards to why the bulletin says not to open the pan, it may have to do with the corporate red tape involved with warranty reimbursement. I found this bulletin on Alldata while browsing TSBs for my Avalanche. It's surprising how many TSBs state "don't do this unless this is present or reimbursement of warranty service may be denied."

The labor time of 0.3 hours, I believe, refers to just the installation of the magnets. There's an asterisk that states, "This is an unique labor operation for bulletin use only. It will not be pulished in the labor time guide."

I've attached the rest of the bulletin for those interested in adding magnets on the 4L60E pan.
 
Ive used magnefines but Im moving away from them for spin ons. They weep and too many stories of them exploding.
This is interesting though, as far as the attracted iron particulate altering the characteristics of the solenoids to the point that they work different from what the PCM expects.
 
Originally Posted By: Colt45ws
Ive used magnefines but Im moving away from them for spin ons. They weep and too many stories of them exploding.
This is interesting though, as far as the attracted iron particulate altering the characteristics of the solenoids to the point that they work different from what the PCM expects.


Hence the new design.

https://magnefinefilters.com/category.sc?categoryId=1

These new ones are not un-screwable or made of plastic but metal now.

FWIW: I've used over 10 individual old style Magnefine filters over the years with no problems. I always bought direct from the factory so no issues with Chinese fakes which where out there and hurt their reputation.
 
I had older MF that weeped a very small amount for a while but soon stopped. Never saw one that blew up! I'm waiting to see what the new unit looks like on the inside. I have a few of the old ones left and am not afraid to use them up. I like them because they are such a simple and cost effective filtration solution. I must correct myself in the ferrous percentage I mentioned above... MF claims 99+ percent of ALL ferrous material.
 
Originally Posted By: WhizkidTN
Originally Posted By: Colt45ws
Ive used magnefines but Im moving away from them for spin ons. They weep and too many stories of them exploding.
This is interesting though, as far as the attracted iron particulate altering the characteristics of the solenoids to the point that they work different from what the PCM expects.


Hence the new design.

https://magnefinefilters.com/category.sc?categoryId=1

These new ones are not un-screwable or made of plastic but metal now.

FWIW: I've used over 10 individual old style Magnefine filters over the years with no problems. I always bought direct from the factory so no issues with Chinese fakes which where out there and hurt their reputation.


Hmm, too bad Ive already bought all the filter heads and hardware to run spin ons! Those look good! I wont be afraid to recommend them or offer to install on a friends rig, however. For most people the simpleness of cutting the hose and inserting a magnefine makes it a no brainer. Theres a high amount of commitment that has to go into mounting and plumbing a spin on...
And yes, Ive bought from the website linked. The one on the ATF of my '02 is drooling down onto the frame.
 
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