Long post so take a pee, clean the sand out of your eyes, get something non-alcoholic to drink, get in a comfortable chair.
My goal is not to convince people of the "best" way to change your transmsision fluid, just wanted to share my results and thoughts based on the data.
About a year ago I started a little experiment by doing serial drain
and fills of the transmission fluid of a then new-to-me 97 FZJ80 with 200,000 miles on the clock. It still had it's original 20 year old transmission fluid which had not been touched until I did the first drain and fill.
The first sample of original 20 year old fluid had about 50-100 times the wear metals normally found in a new transmission along wtih some large particles (20-70 microns), the sizes that can cause damage.
The results I got showed it took 7-8 drain and fills (A343F) to get the wear metals back to normal. However the second sample, after the first drain and fill, showed an increase in the particle counts, which demonstrated that just adding some fresh ATF stirred up/released particles into the fluid. Those particle levels slowly decreased along with wear metals with each successive drain and fill.
The particle counts then dropped significantly after adding a cooler line
auxiliary filter; the first post-filter test was done after ~1200 miles.
Based on those results it appears like a good idea when changing your transmission fluid is to first drop the pan before touching anything else to clean the sediment out of the pan, whether it's just a drain and fill or a complete fluid exchange. Even dropping the pan however will not get all the particles as some of them may come from inside the transmission as the new fluid releases them back into suspension, but it's a good start to drop and clean the pan first.
Summary of what I learned by doing this serial drain and fill experiment:
1) Best to drop the pan and clean it before doing anything with the fluid
2) Install an inline filter before doing anything with the fluid, (into the OUT cooler line to catch it before it gets into the coolers where it can be trapped and then released later back into the transmission) and definitely if not cleaning the pan first
3) Doing a complete fluid exchange would be the most efficient method of replacing all your transmission fluid, but the pan should still be dropped and cleaned first, otherwise those particles will be sucked up into the transmission during the fluid exchange process.
4) An inline filter should also be installed before starting the process of a complete fluid exchange and left in place to catch particles that will be released by the new fluid
Having said all that, guessing 95% of Mud 80 owners never drop their transmission pans including me, our transmission aren't failing very often.
But knowing that the particle counts do go up after any change of fluid, it would seem prudent to add an inline filter before stirring up things. IMHO.
One last bit of info: we all have probably noticed when we check our ATF levels there are two parallel dark lines on the rag/paper towel (check yours if you haven't noticed). To try to determine if those marks were metallic particles I magnetized the last few inches of my transmission dipstick, then checked it again after a few days; those two parallel dark lines became much more prominent.
And then, not long after I installed an inline transmission filter, those dark lines of magnetic (ferrous) particles began to get lighter when checking the ATF level on the dipstick. This coincided with the results of my ATF oil sample particle counts, they dropped significantly after adding the inline filter.
Before installing a new OEM radiator in the 97 model I also flushed the Auxiliary transmission cooler with Kooler Kleen to remove any particles
that had accumulated over the past 20 years.
Magnefine filter:
Amazon product ASIN B0787KWZPS
The NTF filter may filter out a bit more (smaller micron) than the Magnefine above, but both have a magnet to catch the most damaging ferrous particles
FWIW
My goal is not to convince people of the "best" way to change your transmsision fluid, just wanted to share my results and thoughts based on the data.
About a year ago I started a little experiment by doing serial drain
and fills of the transmission fluid of a then new-to-me 97 FZJ80 with 200,000 miles on the clock. It still had it's original 20 year old transmission fluid which had not been touched until I did the first drain and fill.
The first sample of original 20 year old fluid had about 50-100 times the wear metals normally found in a new transmission along wtih some large particles (20-70 microns), the sizes that can cause damage.
The results I got showed it took 7-8 drain and fills (A343F) to get the wear metals back to normal. However the second sample, after the first drain and fill, showed an increase in the particle counts, which demonstrated that just adding some fresh ATF stirred up/released particles into the fluid. Those particle levels slowly decreased along with wear metals with each successive drain and fill.
The particle counts then dropped significantly after adding a cooler line
auxiliary filter; the first post-filter test was done after ~1200 miles.
Based on those results it appears like a good idea when changing your transmission fluid is to first drop the pan before touching anything else to clean the sediment out of the pan, whether it's just a drain and fill or a complete fluid exchange. Even dropping the pan however will not get all the particles as some of them may come from inside the transmission as the new fluid releases them back into suspension, but it's a good start to drop and clean the pan first.
Summary of what I learned by doing this serial drain and fill experiment:
1) Best to drop the pan and clean it before doing anything with the fluid
2) Install an inline filter before doing anything with the fluid, (into the OUT cooler line to catch it before it gets into the coolers where it can be trapped and then released later back into the transmission) and definitely if not cleaning the pan first
3) Doing a complete fluid exchange would be the most efficient method of replacing all your transmission fluid, but the pan should still be dropped and cleaned first, otherwise those particles will be sucked up into the transmission during the fluid exchange process.
4) An inline filter should also be installed before starting the process of a complete fluid exchange and left in place to catch particles that will be released by the new fluid
Having said all that, guessing 95% of Mud 80 owners never drop their transmission pans including me, our transmission aren't failing very often.
But knowing that the particle counts do go up after any change of fluid, it would seem prudent to add an inline filter before stirring up things. IMHO.
One last bit of info: we all have probably noticed when we check our ATF levels there are two parallel dark lines on the rag/paper towel (check yours if you haven't noticed). To try to determine if those marks were metallic particles I magnetized the last few inches of my transmission dipstick, then checked it again after a few days; those two parallel dark lines became much more prominent.
And then, not long after I installed an inline transmission filter, those dark lines of magnetic (ferrous) particles began to get lighter when checking the ATF level on the dipstick. This coincided with the results of my ATF oil sample particle counts, they dropped significantly after adding the inline filter.
Before installing a new OEM radiator in the 97 model I also flushed the Auxiliary transmission cooler with Kooler Kleen to remove any particles
that had accumulated over the past 20 years.
Magnefine filter:
Amazon product ASIN B0787KWZPS
The NTF filter may filter out a bit more (smaller micron) than the Magnefine above, but both have a magnet to catch the most damaging ferrous particles
Automotive | NTF Filter
NTF designs, tests and manufacturers filters for a variety of industries including automotive original equipment, industrial and off-road construction. We specialize in products which remove the smallest contaminates in fluids, often the most damaging to today’s modern systems. We have the added...
www.ntf-filter.com
FWIW
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