Originally Posted By: 3311
I believe I read somewhere that there is a 30 micron screen on the solenoids in the Allison's. Although I generally agree that premature changing of filters isn't beneficial may potentially cause issues, I don't think it is excessively wasteful to change your filter earlier in this application(Allison autos) based solely on the fact that you would to keep the filter out of bypass as much as possible in order the any potential issues arising in the valve body.
Based on the wix/napa 7701(I use this one) beta ratings of 2/20=15/25 or 50%@ 15 micron and 95%@ 25 microns. The Donaldson, who I believe makes the Ally filters, P550606 has slightly better beta ratings of 2/75=9/25 or 50%@ 9 microns and 98.67%@ 25 microns. The filtration margin of error already looks already looks pretty thin IMO.
I understand there are no combustion by products here but you do get clutch material in the fluid that are not captured by the magnet, so again IMO, there is no harm in this situation changing your Allison spin on filter early, within reason of course. I see no issue if you wanted to follow Allison's 12k mile severe service filter schedule(TES 395) even if you qualify for the General usage schedule.
P.S. Here is the Donaldson Info:
https://dynamic.donaldson.com/webc/WebStore/search/item_detail.html?item=419139
I agree; the Donaldson looks a bit better in efficiency.
As for the combustion byproducts versus clutch material, my point is that soot is FAR more abrasive than clutch material could ever pretend to be. Soot also agglomerates (cojoins and becomes ever bigger) if there is no dispersent additive. Since there is no combustion process in a tranny, there is no soot to deal with for a tranny fluid. Clutch material (to the best of my knownledge) does not exhibit this agglomeration trait.
I do disagree with your comment here:
"I see no issue if you wanted to follow Allison's 12k mile severe service filter schedule(TES 395) even if you qualify for the General usage schedule."
If by "no issue" you mean excluding the topic of cost, then perhaps you're right. But cost is a MAJOR factor to most of us. And when there is a huge amount of proof that says overly-frequent filter changes do NOT improve filtration, then why ignore a factor that could save someone 3-5x more money? When studies and real world data and common sense all point to the fact that filter performance actually improves with age, I fail to see the logic of "more = better". I cannot comprehend the mantra of "new filter = better filter".
You mentioned that a concern would be to keep the filter out of bypass. Is it your position that Allison ignored this topic when spec'ing their filter? Is it your mindset that Allison's OEM FCI of 50k miles under routine service is going to send the filter into bypass? I find that untenable, to be blunt.
Like Jim said; everyone has the freedom to do as they choose, and that's the way we all prefer it to be. But I, for one, do not accept mythology and rhetoric as fact when data and proof state otherwise. What some "feel" and "want" is a lot different than what is "viable" and "needed".
Consider these two statements:
* "I use synthetics and change oil/filters every 10k miles. I realize I'm wasting money, but I'm OCD and it makes me sleep better at night." I could accept that statement because it's an admission of emotional committment, and not logic.
* "I use synthetics and change oil often because it's better." Better than what? Where is the proof of better, in relation to some other option? What criteria were used to define "better"? Wear and cost are paramount in the decision process.
To say it's OK to change out any product much more frequently than required, with no regard for cost, is to mislead people who seek good, solid data to make clear headed decisions. Some people come to this site to actually learn about products and make informed decisions, and we owe them the fair, open response that acknowledges both fact and opinion.
In short, I can accept that OCD fluid/filter maintenance habits make people feel good, but I do not accept the premise than the practice leads to "better" equipment protection because every shred of evidence points to a conclusion otherwise.
