I'd like to disspell a rumor

[javey]

Anyways, what I've heard of is some mechanics telling people that if they have never changed their tranny fluid, not to change it. Why would anybody say this, or even think this? I work for a parts store, and from all the reading I have ever done, it does not say this. As far as I know, the ATF breaks down just like any other oil, gets dirty over time, viscosity changes, and then starts to ruin your transmission. Any ideas?

 

[Dan Whitaker]

Because changing the fluid & filter in an automatic transmission with 100k or more miles that has never had it changed will cause pieces of contamination to break loose due to the fresh cleaning properties.

This will then clog tiny orifices in the valve body and thus transmission failure will result.

 

[DeRocha]

Because changing the fluid & filter in an automatic transmission with 100k or more miles that has never had it changed will cause pieces of contamination to break loose due to the fresh cleaning properties.

This will then clog tiny orifices in the valve body and thus transmission failure will result.

Dan is 100% correct..

 

[javey]

So this is TRUE?!

 

[93TwotoneXLT]

Yes.

 

[javey]

Hmm, thanks!

 

[ezeedee]

along the same lines as this, ive heard you shouldnt run high detergent oil in high mileage engines either, because contaminants in the engine are helping hold seals together and if you wash them away the seal is compromised.

fact or fiction

 

[xFatcatx]

That is NOT TRUE!!!! Do change your fluid and filter every 30,000 miles or more even if it has never been done. Just don't have the transmission FLUSHED with high milage. The flushing is what breaks free worn parts. When you change your fluid you only get about 3-5 quarts out depending on how long it takes you and how you do it, its just like draining oil.

 

[Dan Whitaker]

That is NOT TRUE!!!! Do change your fluid and filter every 30,000 miles or more even if it has never been done. Just don't have the transmission FLUSHED with high milage. The flushing is what breaks free worn parts. When you change your fluid you only get about 3-5 quarts out depending on how long it takes you and how you do it, its just like draining oil.

I'm sorry but I beg to differ. I'm one of the guilty ones that has not changed my tranny fluid. I bought my '97 Mountaineer used in 2001 with 79,000 on it. I now have almost 195,000 on it and I have never changed the fluid or will I at this point.

With this many miles it is going to be due for a tranny rebuild soon enough. Why push my luck.

Also, I'm old school. It was considered voodoo to even think of changing your transmission fluid.

 

[xFatcatx]

Well I don't do Voodoo. We will just have to agree to disagree. Maybe we could get this moved to the Transmission and Transfer Case forum for a more knowledgable opinion? I have been wrong before......once......and it was my wifes fault.

 

[351wExplorer]

i am a mechanic and recommend/do trans flushes at over 100K. im like a mad scientist bringing back old trannies from the dead.

 

[aldive]

I too like the flushes and have done several on friends cars with over 100k miles with no troubles at all.

 

[huntersteve61]

Well this topic can be sworn upon that its ok and that its not. The truth is if you flush the system you can loosen up your clutchs and burn up your transmission but you can just as easily do that by dropping the pan because that still effects pressure upon the entire transmission. With how high the detergency is in transmission fluid changing it on a transmission with over 100K and never having had it done prior is only asking for a slippeage problem. The only thing I would do is possibly a transmission additive. Anyone who wishs to argue I would have to ask that you put your money behind the cost of having a rebuild once you seize someones clutchs together because you changed the entire makeup of the transmission and its been so long that the transmission cannot take such a change. I've seen it done and be ok but I've seen people not even make it off the rack.. So I guess I'd ask... Do you feel lucky? better yet.. Do you have 1200 to spare for a rebuild?

 

[UKExploder]

I've had automatic transmission specialists tell me the same thing Huntersteve61 said, so like he says, ask yourself "do I feel lucky? or do I like my tranny as it is....working!"

 

[xFatcatx]

And you wonder why people ***** about the price of rebuilds and repairs when they dont do the maintence on their vehicles......

 

[Rottie]

Just my opinion, but I have been an engineering technician for a major transmission manufacturer for the last 10 years. I would always recommend changing and flushing the transmission at regular intervals. The only contamination that you will find is clutch dust. This is the blackish residue that you see on the inside of the pan. With the high pressures that the fluid is in during operation, there is no way that this dust can clog any orifice and cause damage. If there are pieces in the trans that are big enough to clog anything, it would have to be actual chunks of friction material coming off of the clutch disks, which means the trans is soon to fail anyway- regardless of a flush. The new fluid and the cleansing solution from a good flush will wash away the dust from the clutch plates and help them return to the way they were originally designed to work. The trans will readapt to the clutch fill rates and fluid volumes in a short time. Just my opinion so nobody yell at me OK?

 

[wood1]

The one question that screams to be asked is...

has anyone out there ever done a flush on an old trans when it has never had the fluid changed and as a result it died?

I ask because my old Ex has never had a fluid change and it works perfect (285,000kms) and I am planning on doing it this week.

Chris.

 

[slpdave]

Well I don't do Voodoo. We will just have to agree to disagree. Maybe we could get this moved to the Transmission and Transfer Case forum for a more knowledgable opinion? I have been wrong before......once......and it was my wifes fault.

I thought I was wrong once but I was actually mistaken. LOL.

 

[BrooklynBay]

The internal filter captures these fragments. If that filter is really filthy, a flush will push these fragments throughout the transmission. So the best thing is to replace that filter as soon as possible. The new ATF might soften up other parts inside of the transmission, but the new filter will capture these pieces. If you want to be safe, try this experiment first. Replace the internal filter, add an external filter, run the old ATF through a clean rag into a container to trap any old fragments, then put the old ATF back into the transmission. Run the vehicle like this for a few thousand miles, then replace both filters, and add new ATF.

 

[N1265]

I simply replace the filter and fluid every 75k or so.... No flush, but I do use max life from valvoline.

over 200k and no signs of trouble yet.