If your manual does not call for mixing ATF in your oil, then you shouldn't do it. Car makers pay individuals large sums of money to design engines. If the engineer didn't think it was worth listing in the manual, then it's probably not worth putting it in your engine.
Using ATF to clean an engine
- Thread starter tuckman
- Start date
- Status
While I agree that ATF is not designed to be in the engine, the reasoning behind your conclusion is not exactly correct.
Engineers don't write manuals, technical writer do. They may or may not consult the engineer, but largely they use technical documents to write the manuals. Then you have marketing, legal and warranty guys influencing the final direction of the manual.
My Mazda's owner's manual, for example, never mentions ATF change or flush, never mind the filter. All it states is to check the level annually and add fluid as needed. So, according to the manual, I should never worry about ATF changes, but we all know that AT life is highly reduced when ATF changes are neglected, and I don't think that anybody on this board would argue with me, if I decided to go against the manual and change the ATF.
If engineers were writing the manuals, we would have tons of maintenance items, we probably never heard of, and not a lot of people would actually understand them
Engineers don't write manuals, technical writer do. They may or may not consult the engineer, but largely they use technical documents to write the manuals. Then you have marketing, legal and warranty guys influencing the final direction of the manual.
My Mazda's owner's manual, for example, never mentions ATF change or flush, never mind the filter. All it states is to check the level annually and add fluid as needed. So, according to the manual, I should never worry about ATF changes, but we all know that AT life is highly reduced when ATF changes are neglected, and I don't think that anybody on this board would argue with me, if I decided to go against the manual and change the ATF.
If engineers were writing the manuals, we would have tons of maintenance items, we probably never heard of, and not a lot of people would actually understand them
Originally Posted By: KrisZ
If engineers were writing the manuals, we would have tons of maintenance items, we probably never heard of, and not a lot of people would actually understand them
And people have enough trouble programming their VCR.
If engineers were writing the manuals, we would have tons of maintenance items, we probably never heard of, and not a lot of people would actually understand them
And people have enough trouble programming their VCR.
MolaKule
Staff member
We need to qualify the time line and chemistries involved in this topic.
Back in the days ('50-'70) when people were running 10W40 and at a minimum, 10W30, the detergency package of those oils were less than that found in ATF.
Putting in a quart of 5W20 ATF before the oil change, not only thinned the oil, but provided a small increase in oil detergency and increased the dispersancy somewhat, because the ATF used naphthenic base oils.
Today, ATF has less detergents and less dispersants than modern engine oils, and offers no real AW protection over that of engine oils.
Of course, adding ATF to an engine which has a 5W20 or 0W20 engine oil is not going to do much with the vicosity, but again, offers no advantage wrt cleaning properties.
In my '62 Chevy with a 283, I too had a modulator diaphram leak in the PowerGlide which fed ATF from the tranny to the intake manifold. The burning of ATF deposited black soot on the plugs and blackended the tailpipe. The pistons affected had a layer of thick sooty deposits on them. If I had a tailgator, I would just back-off on the accelerator, which increased vacuum, and blew out some beautiful smoke which either made him pass or back-off.
Back in the days ('50-'70) when people were running 10W40 and at a minimum, 10W30, the detergency package of those oils were less than that found in ATF.
Putting in a quart of 5W20 ATF before the oil change, not only thinned the oil, but provided a small increase in oil detergency and increased the dispersancy somewhat, because the ATF used naphthenic base oils.
Today, ATF has less detergents and less dispersants than modern engine oils, and offers no real AW protection over that of engine oils.
Of course, adding ATF to an engine which has a 5W20 or 0W20 engine oil is not going to do much with the vicosity, but again, offers no advantage wrt cleaning properties.
In my '62 Chevy with a 283, I too had a modulator diaphram leak in the PowerGlide which fed ATF from the tranny to the intake manifold. The burning of ATF deposited black soot on the plugs and blackended the tailpipe. The pistons affected had a layer of thick sooty deposits on them. If I had a tailgator, I would just back-off on the accelerator, which increased vacuum, and blew out some beautiful smoke which either made him pass or back-off.
Last edited:
Originally Posted By: KrisZ
While I agree that ATF is not designed to be in the engine, the reasoning behind your conclusion is not exactly correct.
Engineers don't write manuals, technical writer do. They may or may not consult the engineer, but largely they use technical documents to write the manuals. Then you have marketing, legal and warranty guys influencing the final direction of the manual.
My Mazda's owner's manual, for example, never mentions ATF change or flush, never mind the filter. All it states is to check the level annually and add fluid as needed. So, according to the manual, I should never worry about ATF changes, but we all know that AT life is highly reduced when ATF changes are neglected, and I don't think that anybody on this board would argue with me, if I decided to go against the manual and change the ATF.
If engineers were writing the manuals, we would have tons of maintenance items, we probably never heard of, and not a lot of people would actually understand them
Point taken. But your reasoning is not an apple to apple comparison. You state your owners manual doesn't call for ATF changes, but you choose to change your ATF. Zero harm can come of that. You are replacing a product (ATF) with the same product (ATF). The question at hand is not what to put into the transmission (we agree that it should be ATF), but weather or not the fluid needs changing. Oil and ATF are to completely different products. One is designed for an engine, one for a transmission. If it is ok to substitute ATF for oil, wouldn't one then be able to run oil through their transmission? For me, I'll trust the egg heads at Ford and Yamaha to tell me what fluids work best in my engine.
While I agree that ATF is not designed to be in the engine, the reasoning behind your conclusion is not exactly correct.
Engineers don't write manuals, technical writer do. They may or may not consult the engineer, but largely they use technical documents to write the manuals. Then you have marketing, legal and warranty guys influencing the final direction of the manual.
My Mazda's owner's manual, for example, never mentions ATF change or flush, never mind the filter. All it states is to check the level annually and add fluid as needed. So, according to the manual, I should never worry about ATF changes, but we all know that AT life is highly reduced when ATF changes are neglected, and I don't think that anybody on this board would argue with me, if I decided to go against the manual and change the ATF.
If engineers were writing the manuals, we would have tons of maintenance items, we probably never heard of, and not a lot of people would actually understand them
Point taken. But your reasoning is not an apple to apple comparison. You state your owners manual doesn't call for ATF changes, but you choose to change your ATF. Zero harm can come of that. You are replacing a product (ATF) with the same product (ATF). The question at hand is not what to put into the transmission (we agree that it should be ATF), but weather or not the fluid needs changing. Oil and ATF are to completely different products. One is designed for an engine, one for a transmission. If it is ok to substitute ATF for oil, wouldn't one then be able to run oil through their transmission? For me, I'll trust the egg heads at Ford and Yamaha to tell me what fluids work best in my engine.
Originally Posted By: outoforder
For me, I'll trust the egg heads at Ford and Yamaha to tell me what fluids work best in my engine.
There is no harm trusting the egg heads, by the issue at hand is thinking outside the box. There are lots of wonderful things that become to be because someone did not listen what should and what should not work.
Lets be open minded. I've heard too many stories how it helped. And not one how it harmed. I've never used it and not intend to do it unless I have neglected engine at hand or oil drinker.
For me, I'll trust the egg heads at Ford and Yamaha to tell me what fluids work best in my engine.
There is no harm trusting the egg heads, by the issue at hand is thinking outside the box. There are lots of wonderful things that become to be because someone did not listen what should and what should not work.
Lets be open minded. I've heard too many stories how it helped. And not one how it harmed. I've never used it and not intend to do it unless I have neglected engine at hand or oil drinker.
Does using fluids for their designed and intended applications make me close minded? hahahaha. Your engine, your dime, your time. The basic point I am trying to make is that it makes me laugh reading about guys who try to come up with next best after market gimmick. "I know it says to fill with 5 quarts of approved motor oil, but I'll put 4 and 1 quart of ATF because that works better." Call me crazy, but I suspect there is a reason that oil goes into the engine and ATF in an AT. But hey, if you get better results and performance from the oil/atf mixture, then I guess the egg is on my face.
- Status