Ford Transmission and external magnefine filter

387K miles? Wow! That's rare for the 2003 model tranny. I have one too.

The Magnefine in line filter was installed after Ford paid for some kind of transmission work--probably a warranty claim. And they also spec. the use of the filter whenever a OEM rebuilt 4R100 is installed.

I finally bought my fifth wheel trailer, and am preparing my 2003 F250 for towing. I've bought 20 quarts of ATF, a TruCool auxiliary cooler and a new in pan filter.

Keep the filter and change it religiously every 20K or so.

tvman44 wrote:
Is that with a 7.3L and if so what year?

Mine is a V10, but it is also a 4R100. The V10 and 7.3L version of the 4R100 are the same. Even the torque converters are the same part number. The V10 does run locked all the time however, while the 7.3L will stay unlocked at certain RPMs and throttle position. I'm not sure if its actually a programing difference, or if its a side effect of where the two motors make their power.

Keep it. It works great, and then you never need to drop the pan again when you change the fluid.

I've been using them for a long time now. I change the fluid about every 100,000 miles by draining 6 qts at a time into bucket using the cooler hose, and topping off. At 387,000 miles its so-far-so-good!

mudfuel07 wrote:
You might want to check on Ford-trucks.com. Mark K is over there and he has extensive experience with the 4R100. Also, I think that the Mercon SP has replaced all other fluids.

Mark is on this forum too as Mark Kovalsky, he has even posted recently. If he doesn't post on this thread you can try to PM him.

path1 wrote:
Changing fluid in Ford 2003, transmission type is 4r100. It has an magnefine external filter http://www.ebay.com.au/itm/MAGNEFINE-TRANSMISSION-FILTER-INLINE-MAGNETIC-/260524361006. Took pic and went to Ford guy to get new one. Part guy said to take it off. Only supposed to be on after re-building trans until next trans serving.

Then he got way above my head with line pressure, cooling flow etc and gave good his views why.

Question...Before I eliminate something as important as a filter I would like to have this confirmed.

Ford guy was "part" guy. Not Ford "mechanic". Big difference IMO and both of them have their expertize.

Tried to look up in other web sites , but sort of hard to get straight answer being so many people try to outsmart the OEM. Just want to do right thing, not interested racing or hauling way more than vehicle designed for.

Are those filters supposed to be taken off at first trans servicing after re-build?

Thanks

I highly recommend you keep it on there and replace it every 15 to 25K miles. This filter is as you found out installed after either a tranny failure or rebuild and is typically installed after the stock coolers. The reason is after a failure debris will get lodged in the cooling lines and especially in the two tranny coolers and unless all the lines and both the coolers (one is internal to the radiator and basically requires the radiator to be replaced) are replaced you can NEVER FLUSH all the debris out so as a cost saving measure FORD installs it for added protection. They found failure to do this resulted in redundant tranny failures from contaminated coolers in short order. Thus I would question the advisability of removing it after only one tranny service interval, but the risk should go down over time. However, for the minimal cost and positive benefits I would not eliminate it and in fact many of us installed it even w/o a tranny failure as just added protection. I have been running this filter on my tranny (also a 4R100) since 2002 and for over 65K miles with 3 changes so far. I even have one installed on my power steering for protection there. This filter does a FANTASTIC JOB since it has both a very powerful "earth" type magnet and a paper filter and includes bypass function if something should happen and it clogs. I have even done one post mortem on one with pics and what it collects is just as much as you normally see on the magnetic tranny pan drain plugs. I put mine on before anything happened at around 20K miles from new and installed it pre coolers to get additional protection of the coolers.

You need to double check since mine if on a 7.3L engine and tranny, but I'm almost positive you need the 3/8" size and the link you showed was for a 1/2". You can either get one from FORD or directly from Magnefine.

Now my info is somewhat dated since I have like 6 or 7 of these on hand for use and haven't kept current on any potential changes in it's recommended use since around 2007 so let me know if you have anything that says something different than what I'm posting here and include the source and I will check it out and report back.

P.S. I see after my initial post a recommendation to see what Mark K. says and I second that if you can get ahold of him and I would go with whatever he said "for the most part" ... except if he says to remove it I would want an good explanation of why from him, but in the end he IS THE TRUE EXPERT HERE.

Larry

You might want to check on Ford-trucks.com. Mark K is over there and he has extensive experience with the 4R100. Also, I think that the Mercon SP has replaced all other fluids.

Call ford customer support. I have found them to be very helpful.