transmission flush in older car?

[Homerboy]

So I have an older Honda Odyssey with 165K miles on it. Admittedly, the transmission fluid has not been changed in quite some time (I honestly can not tell you when it was changed last. I just simply don't know)

I was planning on doing a flush this weekend, but was reading that it is often not recommend on older cars with an over due transmission flush. Mainly due to the newer fluid being "too slick" for what is likley a worn down transmission. The newer fluid will cause the gears to clip more causing more damage over time.

Any truth to this? Or is the internet full of lies?

 

[pauldun170]

So I have an older Honda Odyssey with 165K miles on it. Admittedly, the transmission fluid has not been changed in quite some time (I honestly can not tell you when it was changed last. I just simply don't know)

I was planning on doing a flush this weekend, but was reading that it is often not recommend on older cars with an over due transmission flush. Mainly due to the newer fluid being "too slick" for what is likley a worn down transmission. The newer fluid will cause the gears to clip more causing more damage over time.

Any truth to this? Or is the internet full of lies?

What year Odyssey? Whats the owners manual recommendation?
Maintenance schedule could be 90K or it could be 30K.
example
https://techinfo.honda.com/rjanisis/pubs/om/SI9999/SI9999O00132A.pdf


When it comes to internet folklore, there is a Honda disclaimer at the back of the folklore quick reference guide.

 

[lxskllr]

I wouldn't do a flush. Drain and fill maybe, but not a flush. At 165k I'd be inclined to just leave it alone.

 

[HotJob]

Never heard that. I HAVE heard of torque converters going bad because the transmission fluid wasn't changed.
I did a drain and fill on a 2006 Toyota Highlander with 200K+ miles on it. It did help dampen a roar that had developed in the transmission after a head gasket change. Go ahead and change the fluid. Not sure that flushing the transmission would remove any more varnish from old fluid than just a change, but I am very confident it won't hurt.

 

[dave_the_nerd]

That's not a thing. The internet is full of lies.

What is a thing is doing a transmission flush to "fix" a worn out transmission which fails shortly thereafter anyway. So omg the flush killed my transmission.

 

[HarryLui]

Why change transmission fluid? Save the the money and put a rebuild transmission in when it dies.

 

[monkeydelmagico]

What is the condition of the fluid? If it's burnt smelling or discolored I'd go ahead and do a fluid change. You can also send some in for testing: https://www.blackstone-labs.com/transmission.php

 

[Pacfanweb]

That's not a thing. The internet is full of lies.

What is a thing is doing a transmission flush to "fix" a worn out transmission which fails shortly thereafter anyway. So omg the flush killed my transmission.

Pretty much this. There aren't huge deposits of "gunk" inside your tranny, just waiting for a flush to set them free to wreak havoc.

Change the fluid. If it fails soon after, it was going to fail anyway. It's about like folks who get the flu after getting a flu shot thinking that's why they got it. It's not.

Put it like this: If you were say, 10,000 miles overdue for an oil change, would you still change it? Or just keep driving it and ruining your engine even more? Trans fluid is a longer interval, but same concept.

 

[PottedMeat]

So I have an older Honda Odyssey with 165K miles on it

is it the cool second generation one with the grenading 4 speed or the hawt 5 speed?

 

[TonyH]

Do not flush your transmission!

Older Hondas are known for the clutches in the drums, and the torque converter, for coming apart. The new transmission fluid, with its detergents, will loosen deposits from those clutches inside the unit. Those deposits will then go into the filter and clog it. With Hondas you can't change the primary filter. If you do anything at this point, simply do a drain and fill.

 

[Homerboy]

Thanks everyone. I didn't do a flush. Did a drain and fill.

 

[Zivic]

Thanks everyone. I didn't do a flush. Did a drain and fill.

maybe I missed it, but you never stated the year..

I have a 2009. I follow the maintenance minder to a T. Ive done 3 drain fills in my vans 132K miles. These vans are not supposed to be flushed. Instead, when it calls for a trans service, you do a drain, fill 3 times. after each fill, you drive the car up to highway speed. reading up on owners forums, some just opt to do a single drain and fill each time they change the oil

 

[A5]

maybe I missed it, but you never stated the year..

I have a 2009. I follow the maintenance minder to a T. Ive done 3 drain fills in my vans 132K miles. These vans are not supposed to be flushed. Instead, when it calls for a trans service, you do a drain, fill 3 times. after each fill, you drive the car up to highway speed. reading up on owners forums, some just opt to do a single drain and fill each time they change the oil

That's insane. Probably does nothing for them besides wasting money.

 

[Zivic]

That's insane. Probably does nothing for them besides wasting money.

not really. only a portion of the trans fluid comes out in a drain... something around 50%. you do the 3x method to get a high percent of it changed out

 

[mindless1]

^ BUT is there proof this makes any difference? I could see doing that if you're doing tranny fluid ONCE every 100K mi, but no way does it need a 50% exchange with every oil change or a triple change 3 times in 132K miles, except possibly a severe situation like a bank robbery getaway vehicle or towing a lot, a situation where the fluid is overheated.

 

[Zivic]

^ BUT is there proof this makes any difference? I could see doing that if you're doing tranny fluid ONCE every 100K mi, but no way does it need a 50% exchange with every oil change or a triple change 3 times in 132K miles, except possibly a severe situation like a bank robbery getaway vehicle or towing a lot, a situation where the fluid is overheated.

honda doesn't have the best reputation for their transmissions. some opt to do a single drain fill every oil change (5-7k miles). I follow the maintenance minder that calls for a 3x drain fill every 35k miles or so. For me that is about every 30 months. doesn't seem like a lot to me..

 

[mindless1]

Hmm, considering most transmissions are now "filled for life", and before that went closer to 200K than 100K mi without a change, it seems like a lot to me. So much for honda reliability.

Spend enough on doing that and you could have just kept the money in the bank, paid vehicle off sooner, whatever and had the cost of a rebuilt tranny covered.

 

[HitAnyKey]

Hmm, considering most transmissions are now "filled for life", and before that went closer to 200K than 100K mi without a change, it seems like a lot to me. So much for honda reliability.

Spend enough on doing that and you could have just kept the money in the bank, paid vehicle off sooner, whatever and had the cost of a rebuilt tranny covered.

Most Vans and SUVs have maintenance requirements for their transmissions. Drain and Fill is all you need. Flush is just a cash grab IMO. The key is to follow the manual to the letter. Transmissions are not as durable as you think. Once the fluid becomes ineffective your basically destroying your transmission everytime you drive it.

 

[mindless1]

^ And the manual for most in the last decade usually states either filled for life or once every 100K mi or so, to replace it, not flush or triple drain/fill. Transmissions are more durable than you think, unless poorly designed or abused to the point of cooking the fluid. Seeing the way some people drive their (little) cars, I do feel that many people abuse their vehicles, thinking that moar HP means go moar faster.

 

[TurtleCrusher]

Hmm, considering most transmissions are now "filled for life", and before that went closer to 200K than 100K mi without a change, it seems like a lot to me. So much for honda reliability.

Spend enough on doing that and you could have just kept the money in the bank, paid vehicle off sooner, whatever and had the cost of a rebuilt tranny covered.

Before my Fit was totaled I could tell the transmission would be the first thing to go out of anything. I had it to 180k and flushed the transmission at 150k. Didn't sound the same after, and I had zero issues beforehand. Still shifted perfectly, just louder.

Had to have been the most reliable vehicle I've seen though. Stock everything besides the cat, brakes and serpentine pulley tensioner. Literally everything else was factory, 10 years and 180k later.

 

[Pacfanweb]

^ And the manual for most in the last decade usually states either filled for life or once every 100K mi or so, to replace it, not flush or triple drain/fill. Transmissions are more durable than you think, unless poorly designed or abused to the point of cooking the fluid. Seeing the way some people drive their (little) cars, I do feel that many people abuse their vehicles, thinking that moar HP means go moar faster.

By "most", do you mean Hondas? Because "most" cars most certainly do not have filled for life transmissions. The intervals have certainly become longer, but they DO require fluid changes.

That crap about a flush causing "deposits to break loose inside your transmission"....that's a load of it.

What the hell do you think new fluid is going to do? Trans fluid has detergent in it. New fluid is going to scour out the trans, too. All a flush does is change it all, instead of just "most" of it. I'll take my chances with all-new fluid.

 

[mindless1]

^ No I wasn't thinking of Honda. Both some foreign and domestic like Ford or BMW, have had lifetime tranny fluid for over a decade now, maybe closer to 20 years.

A flush can cause deposits to break loose, but granted that's one of those tangents that it could happen to some people but it doesn't mean it's going to happen every time or even more of the time unless the tranny was in really bad shape already, like overheated and it broke down the fluid.

Yes new fluid with new detergent can also break deposits loose in chunks sufficient in size to cause clogs. It's another situation where it depends on the state of the specific tranny in question including its design and the driving environment and driver habits.

Take each vehicle on a case by case (and by design) basis. On most vehicles without tranny design defects you can in fact drive it for the viable lifetime with no tranny failures using the original fluid if not driving in a style or environment where the fluid gets cooked. As much as some like to suggest manufacturers are evil and calculate when a warranty is over, they have also kept records of repair work and made lifetime fluid specs based on them.

The thing that seems ironic to me is people who state it's so important because their make/model/year has failures if you don't. That's called a defective design, not "changing it is important" in an global sort of way that applies to anything other than defective designs or abusive drivers or severe duty environments.

I see the same nonsense from people with defectively designed brake systems, saying it's really important to change fluid every year or two. No it's not, unless it was a crap design or you're a race car driver who pushes it to the edge (or rob a lot of banks, lol).

 

[Pacfanweb]

Agree with most of that.

A properly maintained transmission shouldn't have deposits of crud all over it. If they do, that's a crappy transmission, and it's going to have these issues whether you flush or drain/refill. So might as well flush...at least you'll have all clean fluid, and no old crap if it doesn't cause a problem.

One note: When I'm talking flushes, I'm referring specifically to the machines that are simply fluid exchangers, that use the tranny's own pump to move the fluid and no external pressure. Those cannot cause a problem simply by virtue of the act of flushing. The ones that use external pressure typically don't hurt anything, but there is some potential on some models. But the exchanger types are perfectly okay. With the, it's down to the conversation we're having here about "is this a crappy design or not?"