The dangers of flush machines

Joined
Sep 16, 2007
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St. Louis, Missouri
Good info from AutoTechRepair.Suite101 : Who Recommends Flushing As Maintenance? The shops that want to sell you the engine or transmission flush charge anywhere from $49.95 to $99.95, not including a new engine or transmission. Those are extra. And they state quite emphatically that it is recommended that it be done. But who actually recommends that it be done? I checked with GM, Ford, Chrysler, Nissan, Honda and several other new car manufacturers and not one recommended an engine or transmission flush as routine maintenance. In fact, they specifically don't recommend it at all!! The new car dealerships that do sell them use the implication that since they are the dealer that it must be the factory that recommends it. And if they do say the factory recommends it, they are flat out lying to you. The only ones who do recommend flushing as a maintenance procedure are the companies that sell the flush machines and the shops that buy them. The flush machine manufacturers state quite clearly in their operating manuals not to use their machines on "high-mileage vehicles". That simple statement proves that flushing is not a safe procedure. It also absolves them of any responsibility of any damage that may occur due to the use of their equipment. This leaves the shop wholly responsible for anything that happens and the cost of correcting the damage that occurs. The Dangers Of Flushing... Flush machines do what they say; they force high pressure cleaning solvents back through the engine and transmission and clean out some of the accumulated junk that has formed. Now engines have small passages and galleries through which oil or automatic transmission fluid flow and there are one-way valves that keep the fluids from backtracking for whatever reason. By using an aggressive cleaning procedure like flushing, large chunks of accumulated sludge are broken off and forced backwards through these galleries and valves and, more often than not, lodge tightly and block them. This cuts off the normal flow of the fluid and causes lack of lubrication in an engine and abnormal or no shifting in a transmission. The results are expensive repairs, or more often, engine or transmission replacement.
 
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I only know a few people who have had the transmission flush, and every one of them said it never shifted right again. I've never heard of any problem from draining by pan removal.
 
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I'm a firm believer in the driveway poor man's do it yourself in a 5 gal. pail flush.
 
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First time I heard of a trans flush was from Jiffy boob. It must be a high profit service for them because all the dealerships bought a trans flush machine.
 
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I have never seen a transmission flush machine that "forces high pressure cleaning solvents back through the ... transmission...." The only ones I've seen are simple fluid exchange machines that allow the transmission's own pump to fill one reservoir from the cooler line, and that causes a diaphragm to move pushing new fluid through the cooler return line back to the transmission. I'm not saying that pressure solvent machines don't exist, just that there are more than one type of "flush" machine.
 
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There's one outfit that has an internally powered forced circulation machine that's used for engines and transmissions. It adapts to oil filter bosses and the drain plugs and "power flushes" the engine by force feeding cleaning agents through the lube system. This would be hard to do with all automatics. I know my simple 30rh (904) has an ADBV in the converter that would surely make forced back flushing complicated. I could see running the pump while infusing a solvent in line ..letting it circulate around for a bit then replacing it .. A fluid exchange machine ..as the vast majority are ..should be 100% innocuous to trans performance ..other than the performance difference that new fluid provides. There's no shock ..no foreign agent ..it's a 100% seamless para-in process exchange. The reports of odd shifting and whatnot can just be some consumers and vendors not being able to cope with the overcomplicated learning transmissions that somehow need to adapt constantly to fluid condition to enable them to provide those "velvety smooth shifts".
 
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Back in 2001 I had a trans fluid change at Iffy Lube. Within weeks the transmission went south. They used one if them there machines. Nuff said.
 
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 Originally Posted By: pcoxe
I only know a few people who have had the transmission flush, and every one of them said it never shifted right again. I've never heard of any problem from draining by pan removal.
I had my Tranny flushed 3K miles ago. It shifts as good as new. Better than before the flush.
 
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 Quote:
That simple statement proves that flushing is not a safe procedure.
That proves nothing of the sort. It proves that if a high mileage transmission has never been flushed it has too much accumalated debris to flush safely.
 
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 Originally Posted By: Hermann
Back in 2001 I had a trans fluid change at Iffy Lube. Within weeks the transmission went south. They used one if them there machines. Nuff said.
how long had the fluid been in there prior? what was the condition of the trans prior to the "flush"?
 
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 Originally Posted By: DeeAgeaux
 Quote:
That simple statement proves that flushing is not a safe procedure.
That proves nothing of the sort. It proves that if a high mileage transmission has never been flushed it has too much accumalated debris to flush safely.
Exactly. I've done tons of trans flushes with the flush machines and the only ones that ended up having problems were the trannies that had high mileage and poor fluid maintenance. In those instances I ALWAYS warned the customers of the potential problems that could arise and asked them to sign the paperwork where I had written the warning before I would do any work at all. As someone said in an above post. Most of the machines let the trans pump do the work so there are no higher pressures FORCED through the system at all. That article above was written by someone who either A) took a vehicle in with 100+k fluid in it and the tranny went out, or B) just doesn't like the process and has been misinformed. The manufacturers are going to stick to their book info whether it's correct or not. Even if there was a maintenance item or process that would do the vehicle very well and have no downfall at all... the manufacturer wouldn't recomment it if they didn't put in in their literature.
 
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Thousand Oaks, CA
 Originally Posted By: Built_Well
Good info from AutoTechRepair.Suite101 : Who Recommends Flushing As Maintenance? The shops that want to sell you the engine or transmission flush charge anywhere from $49.95 to $99.95, not including a new engine or transmission. Those are extra. And they state quite emphatically that it is recommended that it be done. But who actually recommends that it be done? I checked with GM, Ford, Chrysler, Nissan, Honda and several other new car manufacturers and not one recommended an engine or transmission flush as routine maintenance. In fact, they specifically don't recommend it at all!! The new car dealerships that do sell them use the implication that since they are the dealer that it must be the factory that recommends it. And if they do say the factory recommends it, they are flat out lying to you. The only ones who do recommend flushing as a maintenance procedure are the companies that sell the flush machines and the shops that buy them. The flush machine manufacturers state quite clearly in their operating manuals not to use their machines on "high-mileage vehicles". That simple statement proves that flushing is not a safe procedure. It also absolves them of any responsibility of any damage that may occur due to the use of their equipment. This leaves the shop wholly responsible for anything that happens and the cost of correcting the damage that occurs. The Dangers Of Flushing... Flush machines do what they say; they force high pressure cleaning solvents back through the engine and transmission and clean out some of the accumulated junk that has formed. Now engines have small passages and galleries through which oil or automatic transmission fluid flow and there are one-way valves that keep the fluids from backtracking for whatever reason. By using an aggressive cleaning procedure like flushing, large chunks of accumulated sludge are broken off and forced backwards through these galleries and valves and, more often than not, lodge tightly and block them. This cuts off the normal flow of the fluid and causes lack of lubrication in an engine and abnormal or no shifting in a transmission. The results are expensive repairs, or more often, engine or transmission replacement.
This post is full of misinformation. Ford, GM, Chrysler, and other manufactures sell "transmission fluid exchange machines" in their dealer equipment catalogs. Most (but not all) dealers don't buy the machines. Instead, most have machines loaned to them from their "snake oil" suppliers. Some transmission designs (such as the Ford Explorer 5 speed automatic) would be nearly impossible to change fluid without such a machine as they have no dip stick tube to fill the transmissions with. The catalogs specifically say "the only approved method of exchanging transmission fluid" for certain transmissions and "highly recommended for all others". There is no warning in the catalogs warning you not to exchange fluid on high mileage cars. In fact, the installers train just the opposite. I have worked in shops that have used these fluid exchange machines on literally thousands of cars WITH NO ADVERSE EFFECT, INCLUDING HUNDREDS OF HIGH MILEAGE ONES WITH PUTRID FLUID. Engine oil flush machines work very differently. The one sold by Bilstein works very well. I'm sure others do to. The only "snake oil" element to them is that the service tends to be oversold, to customers that have no need for the service. I don't know the motivation of the person that published that B*S*, but you can tell him to fold it sideways (with sharp edges) and stuff it where the sun don't shine. It is that useless. Now in the hands of untrained or improperly trained people, it can be very dangerous, just as playing field hockey on a busy freeway. But those that can screw up an oil change from cross threading oil filters and drain plugs and dumping the oil into the wrong hole, they can surely screw up a transmission too.
 
Joined
Apr 11, 2003
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Cincinnati
 Originally Posted By: Big Jim
 Originally Posted By: Built_Well
Good info from AutoTechRepair.Suite101 : Who Recommends Flushing As Maintenance? The shops that want to sell you the engine or transmission flush charge anywhere from $49.95 to $99.95, not including a new engine or transmission. Those are extra. And they state quite emphatically that it is recommended that it be done. But who actually recommends that it be done? I checked with GM, Ford, Chrysler, Nissan, Honda and several other new car manufacturers and not one recommended an engine or transmission flush as routine maintenance. In fact, they specifically don't recommend it at all!! The new car dealerships that do sell them use the implication that since they are the dealer that it must be the factory that recommends it. And if they do say the factory recommends it, they are flat out lying to you. The only ones who do recommend flushing as a maintenance procedure are the companies that sell the flush machines and the shops that buy them. The flush machine manufacturers state quite clearly in their operating manuals not to use their machines on "high-mileage vehicles". That simple statement proves that flushing is not a safe procedure. It also absolves them of any responsibility of any damage that may occur due to the use of their equipment. This leaves the shop wholly responsible for anything that happens and the cost of correcting the damage that occurs. The Dangers Of Flushing... Flush machines do what they say; they force high pressure cleaning solvents back through the engine and transmission and clean out some of the accumulated junk that has formed. Now engines have small passages and galleries through which oil or automatic transmission fluid flow and there are one-way valves that keep the fluids from backtracking for whatever reason. By using an aggressive cleaning procedure like flushing, large chunks of accumulated sludge are broken off and forced backwards through these galleries and valves and, more often than not, lodge tightly and block them. This cuts off the normal flow of the fluid and causes lack of lubrication in an engine and abnormal or no shifting in a transmission. The results are expensive repairs, or more often, engine or transmission replacement.
This post is full of misinformation. Ford, GM, Chrysler, and other manufactures sell "transmission fluid exchange machines" in their dealer equipment catalogs. Most (but not all) dealers don't buy the machines. Instead, most have machines loaned to them from their "snake oil" suppliers. Some transmission designs (such as the Ford Explorer 5 speed automatic) would be nearly impossible to change fluid without such a machine as they have no dip stick tube to fill the transmissions with. The catalogs specifically say "the only approved method of exchanging transmission fluid" for certain transmissions and "highly recommended for all others". There is no warning in the catalogs warning you not to exchange fluid on high mileage cars. In fact, the installers train just the opposite. I have worked in shops that have used these fluid exchange machines on literally thousands of cars WITH NO ADVERSE EFFECT, INCLUDING HUNDREDS OF HIGH MILEAGE ONES WITH PUTRID FLUID. Engine oil flush machines work very differently. The one sold by Bilstein works very well. I'm sure others do to. The only "snake oil" element to them is that the service tends to be oversold, to customers that have no need for the service. I don't know the motivation of the person that published that B*S*, but you can tell him to fold it sideways (with sharp edges) and stuff it where the sun don't shine. It is that useless. Now in the hands of untrained or improperly trained people, it can be very dangerous, just as playing field hockey on a busy freeway. But those that can screw up an oil change from cross threading oil filters and drain plugs and dumping the oil into the wrong hole, they can surely screw up a transmission too.
+1
 
Joined
Dec 7, 2003
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Florida, Cape Coral
My local Pennzoil franchise will not flush any AT with over 100,000 miles. I think the warning of the original post were exaggerated, I have never allowed any of my ATs to be flushed. I don't believe in life-time fluids and do a plug drain and refill every 30,000 miles. Too many personal friends have has issues within 10,000 miles of a flush and the AT was excellent before the flush. A flush has not been recommended in any owner manual maintenance section on any vehicle I've owned. Sometimes dealers have a separate agenda that is supported by their own catologs of ways to make more money. Ed
 
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Sometimes OEMs have a seperate agenda. Like CYA from any legal exposure. Saying "NO" is very easy. Also, do OEMs want transmissions and powertrains that last 1 million miles? Two? How hard would it be to sell cars? Only to superfulous people wanting to make fashion/class/power statements with their cars. I have not had one friend,aquantince,or family member that has had failures/problems as a result of a tranny flush.
 
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Guilford, CT
 Originally Posted By: DeeAgeaux
Also, do OEMs want transmissions and powertrains that last 1 million miles? Two?
Yes. That kind of reputation would sell a TON of cars.
 Originally Posted By: DeeAgeaux
How hard would it be to sell cars?
See above.
 Originally Posted By: DeeAgeaux
Only to superfulous people wanting to make fashion/class/power statements with their cars.
Which is just about everyone in this country... Everyone wants the car that lasts a million miles, even though they're gonna trade it in at 30k anyway.
 
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Mar 31, 2009
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Mi
I have heard lots of horror stories after a flush,does not shift right and I know a transmission shop I know very well.They do lots of valve body cleanings to remove the dirt,crud,clutch material and metal shavings out after a flush with the machine was done
 
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Lugoff, SC
I flush my transmission as soon as the oil starts to get dark. The first flush is always the worst one. Every flush after that, the fluid usually comes out only slightly darker than the fluid going in. I have flushed hundreds of transaxles and the only ones that give me a problem are GM transaxles that have been stuffed into a Swedish car (bad idea).
 
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