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Discussion Starter #1
i have a 1997 dodge caravan and its close to change the tranny oil.

i was over at great canadian oil change and the mentioned i should do a transmission flush. i've hard of it, but than the word "flush" sunk into my head and watched how it was done.

now i did a google search and found some bad reviews about tranny flushing. and "apparently" from what i've read, car manufacturers DONT recommend it at all, its just somewhat of a new gimmick.

apparently it works and does the job, however it can cause some serious issues.

can anyone shine some light in on this that is a mechanic?
 

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Ride Solo
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Not a mechanic, but here's what I did:

I had my van's trans flushed recently at Great Canadian (BTW--get the coupon). The Toyota dealer said that their trans service involved flushing the fluid, so I think the only difference was paying 59.99 vs. 119.00 at the dealer. The trans has worked just fine over the past few thousand km.

I'd be curious to know what problems are attributed to this service.
 
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Well, I don't really see how it can damage anything, but I think it's just hype. Besides, they don't change the filter element when they do a flush. That's like changing the engine oil and not the filter.

Basically all that happens is they put a chemical cleaner into the trans, then hook up a "machine" (which is really just a container with two chambers separated by a diaphragm) in series with the cooler lines. The machine is filled with ATF and an additive. It uses the transmission oil pump to push old fluid into the machine. The pressure of the old fluid coming into the machine pushes the new fluid into the trans.

They say this is better than just a regular auto trans service, (which consists of removing the transmission pan and filter, then refilling) because this only really replaces about 4L (depending on the vehicle) of ATF, because most of the fluid is still in the torque converter. The flush method is supposed to get all the old fluid out. Personally, I would just do what the manufacturer says to do. They built the car, they know what they are talking about (in most cases). Careful though, alot of dealerships will try to tell you that a flush is what the manufacturer recommends. Check your owners manual, it will tell you.
 

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the flush is better in that it exchanges more fluid than a regular sevice.... a regular service drops the pan, changes the filter and installs new fluid, approx 4-6 liters depending on the model. If you service the trans on a regular basis then their is no need to flush, if you tow heavy loads or neglect to service the trans regularly then a flush can be a good thing.

If a problem with the trans comes from a properly done flush the trans was going to fail anyway.
 

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Discussion Starter #5
this is the article that made me question it...

A New "Recommended" Maintenance Item...

In the last few years you were probably asked, or told, by you dealer or quick lube place that you need an engine or transmission flush, because the engine oil or transmission fluid is very dirty. They will tell you that it is recommended that you have it done because your engine or transmission will last longer if it is flushed clean. In that they are correct, a clean engine and transmission will last longer. But is flushing the best way to get a dirty engine clean?

What Is An Engine Or Transmission Flush?

Flushing is the high pressure forcing of fluid back against the normal flow of the fluid. In other words if the normal flow is left to right, the flush would force the fluid right to left. This is accomplished by connecting a machine that will force special solvents back through the engine and transmission. The idea is that by forcing cleaning solvents backwards through the system, it will get all the junk and garbage that has formed over time and "flush" it out of the system. In theory this may be sound, but in actual practice, it's dangerous.

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.

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.

I know this since I recently appeared as a witness in a lawsuit where a person was sold an engine flush that destroyed his engine.

The Facts...

The fact is, if you do frequent engine oil and filter changes and service the transmission every 15,000 miles there is no need for a flush. I have customers that change their oil every 3,000 miles and they don't need to use fancy oils and filters, and after over 100,000 miles, the oil comes out almost as clean as it goes in. They have regular transmission services and their transmission still shifts like new, even with well over 100,000 miles on it.

If you have neglected regular oil changes and you want to do some interior engine cleaning, get the oil and filter changed and replace one quart of motor oil for one quart of transmission fluid. The transmission fluid has a high detergent content that will clean the engine without damaging it. Do this every 3,000 miles and you will clean the inside of the engine slowly and gently.

If you do get a flush, I recommend you do it when you can afford to replace the engine or transmission.
 

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Ride Solo
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AFAIK, the only fluid that went into my trans was trans fluid--there were no cleaners or additives. I didn't know when it had been done last, so I figured it couldn't hurt to start fresh. With the amount of fluid that goes in the trans on my vehicle (~12 litres), it wasn't terribly expensive at $60.
 

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Change it yourself two or three times as often and you won't need a flush.

Auto trannys can be sensitive to fluid level though, so make sure you do it right.

Some vehicles like my 350 Chev didn't have a drain plug in the tranny, making fluid changes a PITA, but you can get a drain plug for $10 from Lordco to make it a painless job.
 

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I'm a mechanic and used to work for Chrysler and what I've found is flushing the fluid can cause trans problems especially when it hasn't been done regularly in the past. The reason is that the dirt and sludge that accumulates on the clutch discs and seals actually fills the space that occurs as they wear so when you do the flush it cleans out that sludge which causes the discs/tranny to slip. Most manufacturers recommend servicing an auto trans every 50kms but Dodge's/Chrysler's are notorious for trans problems especialy pre 2000 so in your case I'd just keep drivin and hope for the best because in those vehicles a trans overhaul usually is just a matter of time.
 

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I'm a mechanic and used to work for Chrysler and what I've found is flushing the fluid can cause trans problems especially when it hasn't been done regularly in the past. The reason is that the dirt and sludge that accumulates on the clutch discs and seals actually fills the space that occurs as they wear so when you do the flush it cleans out that sludge which causes the discs/tranny to slip. Most manufacturers recommend servicing an auto trans every 50kms but Dodge's/Chrysler's are notorious for trans problems especialy pre 2000 so in your case I'd just keep drivin and hope for the best because in those vehicles a trans overhaul usually is just a matter of time.
That's great advice from someone who knows what they are talking about. If I had a vehicle with one of the worst records ever for transmissions I would adopt the "if it ain't broke--don't fix it" approach.

If you are going to have something done, take it to a tranny shop instead of a quick-lube joint (after perusing some of the many "my chrysler transmission is broken" websites).
 

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well, Chryslers are notoriously bad for trannys, especially pre 2000 and lacking service. If you sick to a regular maintence schedule you will be just fine. Do it yourself if you have the ability, but remember if you screw it up a trans rebuild can run multiple thousands of dollars.

As for the flush itself, I can't see how you would force oil backwards through an engine its just not feasable, and every trans flush I've seen or used is done at the cooler lines just exchanging the fluid in the normal flow direction... whether or not the shop uses chemicals and cleaners varies from shop to shop... we currently do not for trans servicing, but do for fuel and coolant systems...
 

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At the Ford Dealership I work for , we perform trans flushes also with a pan drop and filter change. Some of the techs will use the flush machine and others just purge throught the trans cooler lines....the end result is the same...all the old fluids are out and replaced with new. We do up sell a trans flush/additive package but I'm not convined it's necessary if you stick with your service schedule.
 

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Do a pan drop and filter and clean the pan magnet in your tranny every 40,000k and you should be ok for the life of the car (if and a big if) If you turn overdrive off when driving in hilly areas. Make sure not to cycle your OD too much or it will burn your fluid and kill your tranny. Always tow with overdrive off. If you feel your car or truck kicking in and out of overdrive because of the load of terrain you are on simply turn it off. The extra few bucks in gas is far cheaper than 3500-4500 $$ tranny bill.
 

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i have 99 grande caravan that i pull a trailer with loaded with dirtbikes,just service it, chryslers suck..Also if i remember correctly you have to use atf +4 in it otherwise it will slip or shift abnormally.mines got a 3.3l in it and i have put a massive tranny cooler on it and the temp never moves past half even in the hot summer months.
on a side note i have gone through 2 tranny shift modules,luckily there just like a relay box and not in the tranny itself.
 

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You dont' reverse flush an auto trans, what a tool in that article.

Anyhow, I WOULD NOT recommend just flushing the trans if you haven't changed the filter but if you do, I am all for it. Drop the pan, look for tons of crap, bits of tranny etc. Open the filter, again, look for chunks and gold. If all good and your oil is very dirty, go ahead and get it flushed. Most of us don't service the trans so the oil gets abused. Remember, dropping the pan gets you 4-5 litres of oil, the trans can hold up to 15 litres of oil.

I have been doing this for 9 years at my shop and have yet to see a failure caused by it. If you do your services regularly, you won't need to flush but honestly, how many actually do?
 

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Discussion Starter #15
i went to tranny shop, made an appointment for wednesday. so i will splurge the details when i get it done.

they said they will drop the pan, check out everything and work accordingly at that point.

we shall see
 

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If your car is experiencing an exhaust system problem, it's a good idea to take it to a reputable mechanic or a muffler repair shop with experience with car exhaust system repair services in Conshohocken, PA. We are committed to providing quality auto repairs and transmission service at affordable price.
 
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