Hi-Mileage Transmission Flush: Evil or a Must??

In continuing to get my new(to me) minivan ready for a long and cold trip up a mountain in Colorado, the subject of transmission flushes has come up. This van has very high mileage, 170,000 to be exact (Hey I needed a cheap family hauler and it was priced accordingly). My brother in law who I bought it from says he never flushed the transmission or changed the fluid. Sirens went off at that point, but still it was priced accordingly. But now it's time to do something about it.

I've read tons of articles andforum posts about transmssion flushes and came back with two rather dramatic oppinions:

1. OMG TRANMISSION FLUSHES ARE PURE EVIL they will brutally murder your transmission the second you leave the shop. It's designed by greedy mechanics to suck more money out of you. Drain the fluid and top it off, never do anything to stir up that EVIL, murderous sludge.

2. FLUSH IT RIGHT NOW! If you wait one more day your transmission will surely die a horrible death.

...so which is it?? I tend to side with #2, but thought i'd try to get a somewhat educated oppinion. Hell i'll even throw up a poll. I figure we have some decently smart and sensible people here who I somehow trust, not sure why;)

*Edit: He never changed the transmission fluid, not the oil. He changed the oil regularly, good Lord.

What make/model/year is it?
In general, I think FLUSH procedures for old transmissions are bad ideas, as they free all of the worn metal/gunk at once, which can be very bad for modern auto trannies. Also, there is a good chance that some of that gunk is keeping your old seals from leaking.

Drain/fill procedures are terrific for A/T, as the old fluid is very likely dirty and no longer performs within the spec it was made for. It is even a good idea to drain/fill it more than once (with a brief drive in between) to get as much old fluid out of the torque converter as possible, though you will never really get all of it.

I ask about the make/model, because 99-04 Honda Odyssey's have notoriously-weak transmissions and should be treated with kid gloves. DO NOT ever tow with one! If you are going to the mountains, make sure its shifting well. Personally, I would install an aux transmission cooler on any minivan, but especially that generation of Odyssey. If it slips or hesitates going into second, you might have one of the bad, recalled tranny. Do a little research on your VIN with Honda.

Good luck!

I'd lean towards the if it works don't screw with it.

But if you really want to spend the $$$ don't just take it to a Jiffy Lube! I'd also get a AAA membership with Towing before you head to the mountains.

Good stuff here:

I say if it shifts fine and the fluid doesn't smell burnt, then leave it alone. And +1 for AAA.

When the tranny decides to go, it'll probably eat itself one gear at a time. The Camry I had for a while decided one day that it would rather not back up. Then 4th gear let go. Other than that, it still drove fine. I just had to be careful where I parked.

Quote:

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Originally Posted by OZMDD

What make/model/year is it?

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Sorry I didn't specify earlier. It's a 2002 Honda Odyssey, 3.5 V6. I guess the one with the notoriously weak transmission.

Cone-Cerned was telling me about the drain/fill/drive around/repeat method last week when he helped me with the timing belt. I was trying to go a step further due to the rediculous mileage, but if it's really not a good idea then maybe i'll just drain/fill.

Another thing I was reading about is some people reccommended doing a flush but make sure to change the transmission filter at the time, since the clogged filter is usually what does the transmission in(what the article said, I have no idea if it's true). The catch is supposedly Honda denies the filter needs to be changed unless something has gone drastically wrong with the tranny. The filter doesn't look easy/cheap to change either...


The transmission shifts fine through all gears. The only thing that had me concerned is going from reverse to drive sometimes results in a sort of clunk feeling. I think this may be less the transmission and more my wife and I both are used to 5spds and may be gassing it a tad too early.

Thanks for the help guys, this is literraly the first automatic transmission i've driven in my mechanically concious life. I breifly had a couple auto civics when I was 18 or 19.

My Ody is also a 2002 and had 105,000 miles on it when I drained and refilled the transmission. It now has about 117,000 miles on the clock and I have had no problems with the transmission. I will drain and refill again when the time comes.

I put a transmission cooler on the van about a month after we bought it. I have pulled small trailers many miles with no troubles. I have towed the Miata on my big trailer twice, both times to Mineral Wells. Again, no troubles. But, I was much more concerned about stopping than going with all the weight.

I have read that even the M1A1 Abrams has transmission problems when the driver shifts from reverse to drive, and hits the go pedal too hard and too soon. I try to be slow and deliberate with the R to D shift. (I have never driver an M1A1, we still had M48's when I got out.)

If the tranny is good at this mileage, it is unlikely that it is one of the defective ones. The clunk is most likely not a problem the tranny, but related to tranny mounts getting worn or just the switch from fwd to reverse gears. Read some of the Odyssey forums (yes, they have their own!) to understand the tranny issues. Its my understanding that they fail by losing forward gears, eventually only being able to reverse. I attempted to test drive one once that woudl only back-up (you should've heard the salesman trying to scramble up an excuse for that one!)

Again, keep good fluid in it, treat it nice, and I'd expect it to behave like a Honda. I am a fan of tranny coolers, but not a make-or-break item.

Quote:

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Originally Posted by OZMDD

If the tranny is good at this mileage, it is unlikely that it is one of the defective ones. The clunk is most likely not a problem the tranny, but related to tranny mounts getting worn or just the switch from fwd to reverse gears.

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Again, keep good fluid in it, treat it nice, and I'd expect it to behave like a Honda. I am a fan of tranny coolers, but not a make-or-break item.

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I think that's it, feels like the tranny is bouncing.

Tranny coolers: This van has the factory trailer hitch, so i'm assuming it has the 'towing package' already. From what I read this might mean it has a tranny cooler in it. 1. not sure if it has one, if not might be something I look in to. 2. if it has a factory cooler, is it worth anything, should I look into swapping it out for something more beefy??

I know this van has personally made this Colorado up the mountain trip a few times before and handled it like a champ, that being said it's got a ton of miles on it, i'd hate to be stranded.


Any idea if I can get honda tranny fluid some other place than the dealer? I konw online places sell it, but i'd like to not wait for/pay for shipping. I'll see if the price difference is worth the wait.

Quote:

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Originally Posted by Jiggerachi

Any idea if I can get honda tranny fluid some other place than the dealer? I konw online places sell it, but i'd like to not wait for/pay for shipping. I'll see if the price difference is worth the wait.

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Not sure what it's going for from the dealership, but H&A has it for $6.16/bottle...

http://www.handa-accessories.com/odymaint02.html

Foreign Car Parts

From what I've alwasy heard is its a bad idea to flush them if it has high mileage and has never been done on schedule untill 2 different reps told us at 2 different training classes when I worked with NTB that you can flush them at any mileage so long as there is not any driveablity issues already. Take that info for what its worth, btw those were reps from Pensoil and Valvoline.

The term "flush" is incorrect. The quick lube joints use a machine that does a fluid exchange, it splices into a cooler line. As your trans pumps fluid out, their unit pumps new fluid in. It is basically a drain and refill that gets all of the fluid out. If the trans works ok you should be able to drain and refill or have an exchange done with no issues.

Quote:

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Originally Posted by VFR750

The term "flush" is incorrect. The quick lube joints use a machine that does a fluid exchange, it splices into a cooler line. As your trans pumps fluid out, their unit pumps new fluid in. It is basically a drain and refill that gets all of the fluid out. If the trans works ok you should be able to drain and refill or have an exchange done with no issues.

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Exactly what I was told by Pensoil and Valvoline. Yeah but most people use the general term "flush" unless you've worked in a shop. I often use laymens terms when not talking with the techs when I worked at NTB. LOL should've heard some of the analagies I've used to explain an issue to some lady or non-car types!

So what is an actual 'Flush'?? They run some sort of solvent or detergent through the transmission?

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Originally Posted by Jiggerachi

So what is an actual 'Flush'?? They run some sort of solvent or detergent through the transmission?

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The actual "flush" is the fluid exchange VFR750 described and yes most places add a small bottle of special trans fluid conditioner to help clean and it usually has additive to help prevent future wear & tear. Like in a coolant exchange, an additive is added to help prevent corrosion etc. The fluid exhange like VFR750 described is hooked up to the lines and run so that all of the fluid is "flushed" out while the transmission is running. In a drain & fill only about 50% is actually drained out, the rest stays inside the inner workings of the auto tranny...like the valve body etc.

FWIW - I'm under the impression that the difference between "flush" vs "drain" is that the flush is pressurized, so it has the ability to dislodge a lot more crud.

Quote:

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Originally Posted by VFR750

The term "flush" is incorrect. The quick lube joints use a machine that does a fluid exchange, it splices into a cooler line. As your trans pumps fluid out, their unit pumps new fluid in. It is basically a drain and refill that gets all of the fluid out. If the trans works ok you should be able to drain and refill or have an exchange done with no issues.

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I've done this myself on a Ford Escape and a GMC Sierra pickup using the transmission supply and return lines at the radiator; I would assume Honda would be the same. And every transmission filter I've ever replaced looked just as clean as the new one going in so I would believe the claim that replacement is not necessary.

My brother had one of those Odyssey.
He had honda service it, and the trans slowly died.
He had extended coverage, honda refused to cover it and he was left with no choice but to have them replace the trans.
That one lasted 6 months.

He no longer owns a Honda.

^My favorite honda's had 5spds. Drove(drive) the piss out of them meanwhile almost every one of my friends with hondas had their transmissions replaced and wallets emptied.

In light of all this i'm just going to buy some new fluid and drain it myself a few times. A guy I know at a shop is willing to do the cooler line 'flush' or whatever for $50 + fluid, but a driveway refresher should be good enough. All I really need is this van to serve us until the kids get old enough to not get crackers/boogers/fingerprints all over the interior and we'll replace it with a nice big SUV. Hopefully I can find one in 5spd.

Thanks for all the help guys. Learned alot about these fancy auto trannies. Still don't like em, but what ya gonna do...

I've done the "flush" which as VRF750 describes is simply using a machine to capture the fluid as it circulates, replacing it with new fluid. I took 14 quarts of M1 auto fluid to kwik kar and had them do it a few times to my expedition. now at 286k with no issues on another transmission that has a "history". had some other service done and the mechanics cant believe the transmission is original. i wouldnt hesitate.