Any advantage to frequent ATF changes?

[addyguy]

I know that changing engine oil frequently isn't 'cheap insurance', and may actually be somewhat harmful (studies about used oil protecting better...etc...)

But is the same true for ATF?

Have a CD4E in a 2002 Tribute that is known for being a weak transmission. Has a drain plug in the bottom that drops about 4L out of the 10-12 in the transmission, so it is a partial change.

I've had 2 of these partial changes done on this transmission, and after each one, transmission worked noticeably better - transmission is starting to show signs of wear, and engages a bit rough, shudders a bit, and hunts for gears at times. Its not on its deathbed, but it's showing its 150k.

Last partial change was about 4k ago, and fluid is still in great shape - bright red, and at the right level. But in the heat of summer, it seems to be a bit off, not working as crisply as it did right after the drain and fill.

Even though it hasn't been very long, was thinking of doing another drain and fill in the next month or so, to see if it 'perks it up'...so I'm wondering if transmissions benefit from frequent fluid changes, leaving aside that it may be a bit of a waste of $$$...

Any thoughts?

 

[demarpaint]

What mileage interval would you use for your partial change? I've toyed around with your idea from time to time, and think its a good one.

 

[JethroBodine]

Originally Posted By: addyguy
I know that changing engine oil frequently isn't 'cheap insurance', and may actually be somewhat harmful (studies about used oil protecting better...etc...)

Any thoughts?


Yeah...most of those "studies" are done by bookworms who have never gotten any dirt under their fingernails. All machines are damaged by contaminants especially contaminated lubrication systems. So removing those contaminants by shorter lubricant change intervals and better filtration is not harmful. I don't care what Poindexter says...you notice it in your trans right? Well guess what...same thing applies to the whole vehicle. Go ahead and change ALL fluids frequently and you will notice how much longer your vehicle remains in top mechanical condition.

One example of the "damage" a Poindexter can do: For decades GM had journeymen "mechanics" assembling pistons in engine blocks. Measuring with their dirty hands and fitting each piston into the bore correctly. Result: The best engines made on the planet earth.

Then Poindexter decided a robot could do it better and they only needed a "one size fits all" piston. The result: piston slap that sound like a midget inside with a BFH trying to get out when you start your $50,000 Escalade. Poindexter says "they all do that and it's normal"

 

[rshaw125]

I would do 30,000 mile changes and add a transmission fluid cooler. Mercon V I believe.

 

[SatinSilver]

My recommendation would be to add some Lubeguard Red to the transmission. That should help condition all those dried up seals etc.

 

[440Magnum]

Before I go off-topic, I want to say that I don't think you can possibly hurt a transmission with frequent oil changes. Its rarely lack of lubrication that hurts a transmission, its degradation of the *myriad* of friction modifiers that help the clutches work correctly. They're destroyed by heat and torn apart as they do their job crushed between clutch plates, so refreshing them with a frequent partial change is good on all fronts.


Originally Posted By: JethroBodine
.

One example of the "damage" a Poindexter can do: For decades GM had journeymen "mechanics" assembling pistons in engine blocks. Measuring with their dirty hands and fitting each piston into the bore correctly. Result: The best engines made on the planet earth.

Then Poindexter decided a robot could do it better and they only needed a "one size fits all" piston. The result: piston slap that sound like a midget inside with a BFH trying to get out when you start your $50,000 Escalade. Poindexter says "they all do that and it's normal"


Sorry, but I'd take a little cold piston slap Gen III v8 that'll run 300k miles without a hitch *ANY DAY* over a gen-1 small-block Tchebby that'll have a cylinder ridge and a quart/thousand mile oil habit after 200k miles. "Poindexter" is right on that one.

True, there is much beauty in truly handcrafted engines built to high precision by skilled hands, but the last time a mass-production line did that that was probably in the 30s.*Maybe* the 1950s "Whale" Hemis,Cad 331, and Olds Rockets were that good, based on measurements I've seen and heard about from engines dismantled for restoration. But a 1985 Chevy 305 or Chrysler 318? Compared to a 2005 GM Gen III or a 2005 NeuHemi? Get real. You'll find things like .100" deviation from deck face to crank centerline from from front to back of the engine on some of those 70s-90s v8 engines. The mechanics on the line were doing their job, but the tooling (whether automated or manually run) was just shot by then, and its precision was never good enough to even come *close* to a one-size-fits-all piston. Maybe GM went there a little too quick and didn't adopt coated skirts quite soon enough, but the longevity of the engines themselves prove how good "poindexter" did with the design of the tooling that builds them.

 

[SteveSRT8]

Originally Posted By: JethroBodine

Then Poindexter decided a robot could do it better and they only needed a "one size fits all" piston. The result: piston slap that sound like a midget inside with a BFH trying to get out when you start your $50,000 Escalade. Poindexter says "they all do that and it's normal"


Note that we have raised and killed quite a few slappers as our fleet is all GM V8's. Our last one was an 04 just sold with half a million miles on it. That's right, 500k miles! No smoke, no consumption, and no leaks. Slapped like crazy when cold from day one, never changed much at all, nearly silent once warm.

 

[JethroBodine]

Originally Posted By: SteveSRT8
Originally Posted By: JethroBodine

Then Poindexter decided a robot could do it better and they only needed a "one size fits all" piston. The result: piston slap that sound like a midget inside with a BFH trying to get out when you start your $50,000 Escalade. Poindexter says "they all do that and it's normal"


Note that we have raised and killed quite a few slappers as our fleet is all GM V8's. Our last one was an 04 just sold with half a million miles on it. That's right, 500k miles! No smoke, no consumption, and no leaks. Slapped like crazy when cold from day one, never changed much at all, nearly silent once warm.


I have had a few. Family member have had some. Not impressed. You can buy them. I won't. But when you buy them you just lower the standard of acceptable performance one more notch.

 

[SteveSRT8]

Originally Posted By: JethroBodine
Originally Posted By: SteveSRT8
Originally Posted By: JethroBodine

Then Poindexter decided a robot could do it better and they only needed a "one size fits all" piston. The result: piston slap that sound like a midget inside with a BFH trying to get out when you start your $50,000 Escalade. Poindexter says "they all do that and it's normal"


Note that we have raised and killed quite a few slappers as our fleet is all GM V8's. Our last one was an 04 just sold with half a million miles on it. That's right, 500k miles! No smoke, no consumption, and no leaks. Slapped like crazy when cold from day one, never changed much at all, nearly silent once warm.


I have had a few. Family member have had some. Not impressed. You can buy them. I won't. But when you buy them you just lower the standard of acceptable performance one more notch.


It's all old news, they haven't made one in many years now. About 08 in the vans and about 06 in the pickups and cars everybody got coated pistons and all is quiet now. But it is truly the biggest non-issue ever raised as it affected nothing negatively at all.

You must have never had a hot motor with a set of forged pistons. I have a small block Chevy based stroker here that would worry you to death for the first 45 seconds to a minute when it is started cold!

 

[dparm]

Advantage to frequent ATF changes? Contaminated/thinned-out fluids are in there less time, simple as that.

 

[Thax]

Addy for my 01 Tribute which was recently sold , I did frequent drain and refills of the transmission fluid. I would drain the ATF via the drain plug every other engine oil change which worked out to about 8k miles in my tribute. I used DexIII/Mercon in mine , I did not use Mercon V in mine. It always shifted nice , bright red fluid until we sold it at 115k miles. The CD4e is known to be somewhat weak in many applications , however due to increased cooling in the Escape/Tribute seems to do ok . Perhaps adding a external ATF cooler is a good idea in a vehicle with a CD4E.

 

[SwampSurvivor]

Originally Posted By: JethroBodine
Originally Posted By: SteveSRT8
Originally Posted By: JethroBodine

Then Poindexter decided a robot could do it better and they only needed a "one size fits all" piston. The result: piston slap that sound like a midget inside with a BFH trying to get out when you start your $50,000 Escalade. Poindexter says "they all do that and it's normal"


Note that we have raised and killed quite a few slappers as our fleet is all GM V8's. Our last one was an 04 just sold with half a million miles on it. That's right, 500k miles! No smoke, no consumption, and no leaks. Slapped like crazy when cold from day one, never changed much at all, nearly silent once warm.


I have had a few. Family member have had some. Not impressed. You can buy them. I won't. But when you buy them you just lower the standard of acceptable performance one more notch.


Honda had piston slap issues with their J series V6. Is it okay for them too?

 

[JethroBodine]

Originally Posted By: SteveSRT8

You must have never had a hot motor with a set of forged pistons.


I have had 4 to be exact. Different beast. Different reasons. None ever slapped like the 2000. production engines. Plus they got 15w40 or 20w50 oil. So while they did rattle a bit at cold start not one ever slapped. All 4 were GM 454. 385 to 500HP. If you had to worry when you cold started an engine then it wasn't built correctly.

 

[JethroBodine]

Originally Posted By: Miller88
Originally Posted By: JethroBodine
Originally Posted By: SteveSRT8
Originally Posted By: JethroBodine

Then Poindexter decided a robot could do it better and they only needed a "one size fits all" piston. The result: piston slap that sound like a midget inside with a BFH trying to get out when you start your $50,000 Escalade. Poindexter says "they all do that and it's normal"


Note that we have raised and killed quite a few slappers as our fleet is all GM V8's. Our last one was an 04 just sold with half a million miles on it. That's right, 500k miles! No smoke, no consumption, and no leaks. Slapped like crazy when cold from day one, never changed much at all, nearly silent once warm.


I have had a few. Family member have had some. Not impressed. You can buy them. I won't. But when you buy them you just lower the standard of acceptable performance one more notch.


Honda had piston slap issues with their J series V6. Is it okay for them too?


Not for me.

 

[MolaKule]

Quote:
I know that changing engine oil frequently isn't 'cheap insurance', and may actually be somewhat harmful (studies about used oil protecting better...etc...)

But is the same true for ATF?

Have a CD4E in a 2002 Tribute that is known for being a weak transmission. Has a drain plug in the bottom that drops about 4L out of the 10-12 in the transmission, so it is a partial change.]


Not the same with ATF.

Doing drains and refills refreshes additives and reduces the density of particles and solids. Introducing cleaner fluid means the internals are less likely to varnish.

Refreshing any fluid can only help clean the internals.

I just did a series of tests with a synthetic DexronVI equivalent developed here using three vehicles (two domestic GM 4L60E), two foreign) against GM DexronVI FF.

We sampled every 7,500 miles and found that with either fluid, solids showed an increase of 7%.

 

[440Magnum]

Originally Posted By: Miller88


Honda had piston slap issues with their J series V6. Is it okay for them too?


Honda had a lot of cold-engine piston slap for a number of years before GM did... and yes it was OK for them too. Honda builds very good engines, and always has.

Jethro conveniently skipped over the fact that the surge of engines with piston slap isn't ALL due to a changeover to "one size fits all" pistons. For 40 years, automakers introduced a deliberate "flaw" into their engines, offsetting the piston pin away from the centerline of the piston so that the piston would rise "cocked" in the bore on the compression stroke in such a manner that it wouldn't loudly rock in the bore as the crank passed through TDC (piston slap). That deliberate offset hid a lot of sins- sloppy fit in the bore, variation from one cylinder to another. It also introduced a lot of excessive friction on 3 strokes out of 4 in the otto cycle engine. But it did one thing great- eliminated (hid) piston slap. You could have a HORRIBLE piston-to-bore fit, but that offset would make the engine very quiet. And inefficient... Racers had used centered-pin pistons (first forged, then hypereutectic) for 30-odd years before the manufacturers switched over because there is a CLEAR increase in output power and efficiency with centered-pin pistons due to less friction. Racers didn't care about the slap, can't hear it over open headers anyway. The manufacturers moved to centered pins along with hypereutectic pistons, which can be fitted tighter in the bore when cold because they expand less than forged or cast conventional (eutectic) alloys. Tighter, but not tight ENOUGH to totally eliminate cold-engine piston slap without coatings on the skirts. Even without the quieting coatings on piston skirts, GM (and Honda, and others...) were building engines that were demonstrably better in half a dozen ways than the previous quiet engines, but ignorant consumers don't know that and complained about a the rattle.

Biggest tempest in a teacup in the auto industry in the past 30 years, if you ask me. Total non-issue blown out of all proportion by complaints and "class-action" lust on the interwebs.

 

[Donald]

The benefit I see is a "refresh" every so many miles. You drain some ATF with contaminants and add fresh ATF back with new additives. Given that a drain & fill is typically 1/3 or so of the total capacity this might be the way to go.

 

[Nate1979]

Originally Posted By: MolaKule
Quote:
I know that changing engine oil frequently isn't 'cheap insurance', and may actually be somewhat harmful (studies about used oil protecting better...etc...)

But is the same true for ATF?

Have a CD4E in a 2002 Tribute that is known for being a weak transmission. Has a drain plug in the bottom that drops about 4L out of the 10-12 in the transmission, so it is a partial change.]


Not the same with ATF.

Doing drains and refills refreshes additives and reduces the density of particles and solids. Introducing cleaner fluid means the internals are less likely to varnish.

Refreshing any fluid can only help clean the internals.

I just did a series of tests with a synthetic DexronVI equivalent developed here using three vehicles (two domestic GM 4L60E), two foreign) against GM DexronVI FF.

We sampled every 7,500 miles and found that with either fluid, solids showed an increase of 7%.


Sounds interesting. Can you share more technical information?

 

[Jim Allen]

Getting back on topic, the ONLY reason to change ATF before its time is due to contamination.

I've talked a lot in the past about the studies by Eleftherakis and Khalil and they published a good deal of data on it. It was all based on studying transmissions and testing oils at various different mileages and operational situations. The first is change is the most important because the average trans will generate 75 % of it's lifetime amount of contamination within the first 5K miles. In 70K miles, with no change, the oil will have about 265 mg/l of contaminants in it ranging in size from 5-80 um, some 80 percent of them larger than 5 um.

While cleaner is better, E & K discovered that an average automatic will not suffer too many long term effects if the oil cleanliness levels are kept under a 19/15 ISO code. Assuming you did that first oil change to get the break-in/built-in debris out, it might take a while to reach that level but it would likely be reached before the oil could be condemned for other reasons. The simple answer is external filtration, which can easily keep contamination levels below that magic ISO code and allow you to condemn the oil based on factors outside of contaminants. It doesn't take much. In my own rigs, a simple Magnefine keeps the levels at around 17/12... a little better than the new oil I installed.



To go back off topic, you've never heard a slapper until you've heard a Rover aluminum V8 with pistons about 3 thou under the spec. I heard a lot of them. They would run forever that way but new engines aren't supposed to do that so we did a bunch under warranty. I took home crates of pistons and a lot of short blocks from the trash pile at work. Was able to mix & match to get some nice tight engines. In some cases, I resorted to the age-old cure... knurling. The "official" original cause was mismarked pistons. That was true but apparently instead of actually miking the bore and piston and fitting a piston, they just read the stamped numbers on the bores (done by one drunken Brit) and the pistons (done by another drunken Brit) and that was that. At the time thing was going on, the LR factory had beer machines in the cafeteria, hence my "Drunken Brit" comments. I actually don't know how many were really drunk but some of the stuff I saw could only be done by somebody that was completely wasted or didn't give a rat's patoot. Or both. In the late '80s and early '90s, the LR factory in Solihull was an appalling place full of union men who had to commit mass murder before they could be disciplined. Thankfully, things soon changed for the better.

 

[MolaKule]

Quote:
I've talked a lot in the past about the studies by Eleftherakis and Khalil and they published a good deal of data on it. It was all based on studying transmissions and testing oils at various different mileages and operational situations. The first is change is the most important because the average trans will generate 75 % of it's lifetime amount of contamination within the first 5K miles. In 70K miles, with no change, the oil will have about 265 mg/l of contaminants in it ranging in size from 5-80 um, some 80 percent of them larger than 5 um.

While cleaner is better, E & K discovered that an average automatic will not suffer too many long term effects if the oil cleanliness levels are kept under a 19/15 ISO code. Assuming you did that first oil change to get the break-in/built-in debris out, it might take a while to reach that level but it would likely be reached before the oil could be condemned for other reasons. The simple answer is external filtration, which can easily keep contamination levels below that magic ISO code and allow you to condemn the oil based on factors outside of contaminants. It doesn't take much. In my own rigs, a simple Magnefine keeps the levels at around 17/12... a little better than the new oil I installed.


Agree fully with the report and you Jim.

However, for those who cannot install or do not want to install an external Magnafine filter, periodic ATF drains and refills are an excellent way of maintaining their transmissions.