Why does the VTM fluid need changed so often? I get it checked and it always looks clean and I have yet to engage the VTM4 drive capability. I puts lots of miles on my MDX and the dealer in Houston considers any car they sell "severe conditions" driving. How difficult is this to change myself as the place I do the regular service does not stock the fluid and I hate going to the dealer this often.. 55K miles and still loving it...
VTM FLuid Change
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It is next to impossible for you not to have engaged the VTM4 -- though you may not have done so manually. It engages as needed and, I believe, this includes everytime you start moving from a stop. The dealers certainly will encourage you to use the severe schedule, because it's a money maker for them. There are many previous posts on this subject.
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Fat, lots of threads on changing your own VTM fluid - a key thing I recall is to get yourself a pump so you can do a complete fluid change. Do a search on VTM to get the instructions.
As I understand it, VTM kicks in each time you accelerate, then it shifts to front wheel drive.
Also, it's good that it looks clean, really bad karma if it's not . It's more like tranny fluid than motor oil...
As I understand it, VTM kicks in each time you accelerate, then it shifts to front wheel drive.
Also, it's good that it looks clean, really bad karma if it's not . It's more like tranny fluid than motor oil...
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I suppose the only real reason to follow the service intervals is to ensure you have a warranty- but with 55k on yours, who cares?
I'd hate to have a VTM4 failure, and have the dealer ask for receipts showing VTM4 fluid purchases or service....
Others are correct: it is used continuously and is subject to ATF-like abuse NOT like a standard rear differential. If you've never changed it, yours is shot and I would bet money the clutches in the diff have suffered (just one guys opinion...)
Final point: the dealer is wrong. Yes, severe service applies for temperatures above 90F BUT: NOT for the VTM4! Even if the rest of the car requires severe service, the VTM4 only needs it if it is used off road, etc. (read the manual)
Ard
PS have you COMPARED your fluid to new? You'll be surprised....
I'd hate to have a VTM4 failure, and have the dealer ask for receipts showing VTM4 fluid purchases or service....
Others are correct: it is used continuously and is subject to ATF-like abuse NOT like a standard rear differential. If you've never changed it, yours is shot and I would bet money the clutches in the diff have suffered (just one guys opinion...)
Final point: the dealer is wrong. Yes, severe service applies for temperatures above 90F BUT: NOT for the VTM4! Even if the rest of the car requires severe service, the VTM4 only needs it if it is used off road, etc. (read the manual)
Ard
PS have you COMPARED your fluid to new? You'll be surprised....
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Ahh, the pump is to get the fluid into the VTM, as its position renders it impossible to pour the fluid in. The pump is not a sealed, pressurized attachment, as may be with transmission and engine flush systems. A complete fluid change necessitates changing the fluid a total of 3 times and driving the vehicle for 5 minute between each change (forgot which technical document a member got this from, not a TSB) and at $20 per gallon, its needless to say that no one does this.ghost said:
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Partially correct: Yes, the pump is just to get the fluid up into the VTM4 housing. It is not a "flush", so really any pump will do. Just need to overcome gravity.TheyCallMeBruce said:
No, you do not need to do three changes for the VTM4 (in the manual they specific this 3x with 5 min drive for the ATF 'complete flush') The VTM housing can be completely drained from the drain plug.
Ard
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Yep, it seems plausible that the VTM drains completely. But I'm still curious about the multiple drain on the ATF. The only mention of ATF replacement in my '01 manual is 14-138, and refers to only a single refill. Was someone quoting an '02 manual? Can someone with an '02 manual confirm (check back of book index, ATF Replacement)?ardvarkus said:
Exactly where is the information written regarding a complete ATF flush?
Thanks.
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Try the lowly OWNERS manual...page 271 I believe?
"To thoroughly flush the
transmission, the technician
should drain and refill it with
Honda ATF-Z1, then drive the
vehicle a short distance. Do this
three times. Then drain and refill
the transmission a final time."
Admittedly, this appears after a discussion on using non-Honda fluids. I suppose they might be saying if you use a non-honda ATF in a pinch, then you need to thourughly flush with this method.
Using the procedure in the Service manual, you are just 'refreshing' the ATF....
Ard
"To thoroughly flush the
transmission, the technician
should drain and refill it with
Honda ATF-Z1, then drive the
vehicle a short distance. Do this
three times. Then drain and refill
the transmission a final time."
Admittedly, this appears after a discussion on using non-Honda fluids. I suppose they might be saying if you use a non-honda ATF in a pinch, then you need to thourughly flush with this method.
Using the procedure in the Service manual, you are just 'refreshing' the ATF....
Ard
My thought is that a single "drain and refill" will only replace about 30-40% of the old fluid (Honda or other); therefore, the "triple-drain" method would be used to ensure that the majority of the fluid in the transmission is new. If I recall properly, the torque convertor doesn't drain when you remove the transmission's drain plug, so the triple method is required to get it and the rest of the transmission filled with mostly-new fluid. It's a pain, but it's a good idea.
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That's correct- per the service manual, a drain and fill takes 3.49Qt versus 8.66Q for an "overhaul" (i.e. complete fluid exchange...
I did my own ATF change, and did the triple-thing... next time I'll use a shop with a flush machine.
[(8.66-3.49)/8.66] cubed = % of original fluid remaining, assuming perfect mixing, etc (around 20 percent)
Once more gives you 13%, and a 5x gets you ~7%. Cannot understand why Acura does not require a flush machine...
Ard
I did my own ATF change, and did the triple-thing... next time I'll use a shop with a flush machine.
[(8.66-3.49)/8.66] cubed = % of original fluid remaining, assuming perfect mixing, etc (around 20 percent)
Once more gives you 13%, and a 5x gets you ~7%. Cannot understand why Acura does not require a flush machine...
Ard
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Owner's Manual, you mean the book that comes with the car? Need to go look for that. But maybe not. I agree that perhaps the intention is to only triple drain after using non-Honda fluid, and probably more to drive home the point not to use aftermarket.ardvarkus said:
Even if the factory service manual doesn't require a triple drain, I support your idea that it needs to be done anyhow to acheive a true drain as I've also noticed how little fluid really gets drained at a time according to the specs. Will do the same when my time comes. Thanks for the clarification.
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Transmission flushes are a huge controversy among some automotive newsgroups. The usenet group I was formerly associated with constantly bantered with this issue. It piqued my interest and I checked with three of my professional mechanic/service writer friends (2 in independent facilities, 1 at a dealer, not Acura). They all perform tranny flushes as part of their routine work, but they all said they would never, ever flush the tranny in their own cars, or recommend them to friends and families. They have seen unexplained transmission problems pop up frequently after a tranny flush; so often that they can't help but make a correlation. Beause no one has a definitive and provable theory, and it is a big money maker, their facilities continue its use. One of these guys theorize that because the problems show up more likely on older cars, that it may have something to do with higher than normal fluid pressures and strong solvents that end up dislodging gum and varnish. This is the purpose of a flush, but then these clumps travel into small passageways and through tiny valves and consequently partially or fully plug up the openings. They all agree that a simple, multiple drain and fill will fully exchange the transmission fluid. But interestingly, two of the three don't plan to ever have their transmission fluid changed. That even though it flies in the face of every service recommendation, they said they see more problems when people try to "maintain" their transmission, than to just check the level occasionally and leave it alone for the life of the car. Cleaning out tranny pans and replacing filters (MDX has no tranny filter) and pan gaskets, flushing, all seemed to introduce issues and problems. Ironically, the more experienced of the three (22+ yrs) felt that, based on long-term customers, the more often a transmission is serviced, the more likely it will suffer a catastrophic failure in its later years.DaleB said:
Yes, the failures could be blamed on the mechanics, maybe they blow sand grit up into the tranny when the pan is off or something. I don't know, I'm not completely convinced, but the controversy is not isolated, and its enough to make me cautious. For now, no flushes for me. I just got a case of Honda ATF oil for $32 (reg $54) and will just do my own safe and secure triple drain (nice parts guys, gave me a gallon of VTM fluid for free, because it was the last one and was dirty on the outside, but still sealed below the cap).
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Well, you are the second one to mention 'solvents'. Automatic transmissions can be flushed without solvents. I had it done on another car at a transmission shop when I planned to switch to synthetics. Also, the MDX does not have a pan, the flush is done through the fluid coolant lines. Old fluid is displaced by fresh fluid and until it runs clear. Also there is a in-line filter in one of the coolant lines where it enters the transmision. I do not know if Acura dealers replace this with the flushing, according to the service manual it appears it is only replaced with repair service.
Given all that, there is less intrusion even if you replace the external filter than with most automatics. I am not sure myself if I want to do a flush, but have lots of time yet to decide. One member does the standard one time dump of the fluid every other oil change (7500 mi). That sounds like a very prudent way to maintain the tranny without going through the 3X at 30K, since the warrany only requires a one time flush at 30K.
I should also mention the flushing I had done involved running the engine so in effect the transmssion was pumping the fluid (old out, new in) so there were no excessive pressures involved.
Given all that, there is less intrusion even if you replace the external filter than with most automatics. I am not sure myself if I want to do a flush, but have lots of time yet to decide. One member does the standard one time dump of the fluid every other oil change (7500 mi). That sounds like a very prudent way to maintain the tranny without going through the 3X at 30K, since the warrany only requires a one time flush at 30K.
I should also mention the flushing I had done involved running the engine so in effect the transmssion was pumping the fluid (old out, new in) so there were no excessive pressures involved.
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More ATF Flushing Info
Anyway, while doing some searches I noted most transmission shops do not say much about flushing at all. It's seems to be a 'dealer' phenomena, or larger repair shops.
The most important thing I found was that it is imperative NOT to flush or even drain ATF if there is a suspected mechanical problem before it can be diagnosed.
What I did find interesting was the following link. It is the best description of the types of ATF flushing that can be done.
This is a 4Runner website run by some enthusiast. You 4Runner owners might enjoy it. Just go the the HOME page from the flushing article.
http://www.gadgetonline.com/TransFlush.htm
Anyway, while doing some searches I noted most transmission shops do not say much about flushing at all. It's seems to be a 'dealer' phenomena, or larger repair shops.
The most important thing I found was that it is imperative NOT to flush or even drain ATF if there is a suspected mechanical problem before it can be diagnosed.
What I did find interesting was the following link. It is the best description of the types of ATF flushing that can be done.
This is a 4Runner website run by some enthusiast. You 4Runner owners might enjoy it. Just go the the HOME page from the flushing article.
http://www.gadgetonline.com/TransFlush.htm
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Yeah. You flush those too!DaleB said:
Actually, I am serious- I do on my Q45. Every 2 years. (Brake fluid is hydroscopic (sucks up water) and it will loose performance pretty quickly) Racers replace it weekly.
Here's my thinking on flushes (and really this is a belief system, as you can read there is no definitive answer)
Flushing is simply to replace the old fluid.
if you are flushing to CLEAN OUT DEPOSITS - you have not maintained your part (transmission, brake system or Power steering).
If you are flushing regularly, you are already removing sludge/breaddown products, grit, WATER, etc. perhaps even before they deposit. There is then no need to use solvents or drastic flushing regimes.
MOST shops who flush just hook up, run the program, out you go... Oh, have a problem now? Well, it was an old transmission, we need to rebuild. THe better shops will really work the trans to scrub them- but I would agree that once you get past 60k without a fluid change an aggressive flush might be trouble.
On an old trans, perhaps poorly maintained, if you start having shifting problems, I would recommend a VERY aggressive cleaning PRIOR to spending $$$ for a rebuild- it COULD just be crap in the valve body and not blown bands or clutches...
My 2 cents.
Ard
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