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Discussion Starter #1
Recently, my adult son asked why the MDX has a high pitched whistle at about 60mph. Actually, it starts at slightly lower speeds and continues on up to 80mph and beyond. The frequency or pitch of the sound changes relative to speed. The tires were older and I just wrote it off to that. However, after replacing the tires, the whistle/whine is still there.

It is interesting that the sound stops when I remove my foot from the accelerator. So, when coasting, no whistle. If I just touch my foot to the accelerator again, the whistle immediately returns. I don't have to "load" the engine/trans by accelerating or gaining speed. The whistle exists with the cruise set. But, again, as soon as you let off the accelerator, it stops completely.

Anybody have any ideas about this? I think it's been doing it for a very long time. I just grew used to it over the years.
 

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Sounds suspiciously like the dreaded torque converter whine. You can find out for sure by shifting to D4 - if the whine goes away, then you know it's your torque converter lockup circuit. If so, it's annoying, but won't really cause a failure. Some have had luck (including me) reducing the whine by changing the transmission fluid (mine got noticeably quieter every time I did a drain-and-fill). But there are a gazillion or so threads on the subject for your reading pleasure, assuming that's really the issue.
 

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Discussion Starter #3
Thanks habbyguy.

It definitely sounds like the torque converter issue. That makes sense. I'll do the D4 test to confirm. It isn't too much of a nuisance and the vehicle is now 13 yrs old. Hey, we all make some funny noises as we get older.

I'll check the last time I changed the fluid and do one with OEM fluid.

This vehicle owes me nothing. I bought it new and after ~135K miles, so far, not a single failure of any kind. Only maintenance items.
 

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Let us know how that goes. The MDX transmissions are very particular about fluid, and changing the fluid regularly is probably the best (cheapest) insurance you'll ever buy.

I remember one post where he claimed to pretty much eliminate the whine with a combination of some high-end fluid (not sure which) and some Lubegard Shudder Fixx (SIC, I think). I did try the Lubegard SF in mine, and don't think it made much difference though I HAVE had great luck using Lubegard Platinum (regular additive) to fix shifting issues on several really "bad" transmissions.

And yeah, my MDX was crazy reliable - almost nothing broke between 160,000 and 245,000 miles (the period I owned it). A window regulator, HP power steering hose, alternator and had to fiddle with a couple vent control motor units (replaced one, cleaned and lubed the other). I did a bunch of "extra maintenance" to make it a better-driving vehicle, and to keep it running better... but almost nothing "broke". Hope the replacement vehicle works out as well (129,000 mile 2005 Volvo V50 2.4i wagon).
 

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Discussion Starter #5
Update: I was driving the MDX recently and at about 60, got the whine to it's peak audible level. It gets higher pitched as you increase speed. Anyway, I shifted down to D4 and viola' it was gone. Back into D5 and the whine returned immediately. Like an on/off switch going from D5 to D4 and back. It's definitely a transmission noise. Sounds like its' pretty benign but, I plan to do a fluid drain & flush anyway.

I'll update the thread after the fluid change to OEM. We'll see what, if any difference, it makes.
 

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Update: I was driving the MDX recently and at about 60, got the whine to it's peak audible level. It gets higher pitched as you increase speed. Anyway, I shifted down to D4 and viola' it was gone. Back into D5 and the whine returned immediately. Like an on/off switch going from D5 to D4 and back. It's definitely a transmission noise. Sounds like its' pretty benign but, I plan to do a fluid drain & flush anyway.

I'll update the thread after the fluid change to OEM. We'll see what, if any difference, it makes.
Don’t use OEM, it’s not going to do anything. Do a triple drain and fill with Redline D4 and add LubeGard platinum for last fill.
 

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Don’t use OEM, it’s not going to do anything. Do a triple drain and fill with Redline D4 and add LubeGard platinum for last fill.
Maguffin1995, were you the guy who got "total remission" on your torque converter whine? I wish I had read your post when I owned my MDX, because I would have gladly tried Redline fluid (I'm already a huge fan of the LubeGard Platinum additive, which seems to work really well in Honda trannies).

Eurojap, good news on your testing - that confirms that the problem is only torque converter whine. I'd suggest doing what Magauffin1995 suggested. I did get a noticeable reduction in whine every time I did a drain-and-fill, but it never got really "quiet". The other good news is that I can't recall any case of TC whine ending up in any kind of actual failure. If it was an easier fix, I would have just replaced the torque converter in my MDX (they're not all that expensive), but having to drop the front subframe out to do it made me content to just live with a little whine.
 

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Maguffin1995, were you the guy who got "total remission" on your torque converter whine? I wish I had read your post when I owned my MDX, because I would have gladly tried Redline fluid (I'm already a huge fan of the LubeGard Platinum additive, which seems to work really well in Honda trannies).

Eurojap, good news on your testing - that confirms that the problem is only torque converter whine. I'd suggest doing what Magauffin1995 suggested. I did get a noticeable reduction in whine every time I did a drain-and-fill, but it never got really "quiet". The other good news is that I can't recall any case of TC whine ending up in any kind of actual failure. If it was an easier fix, I would have just replaced the torque converter in my MDX (they're not all that expensive), but having to drop the front subframe out to do it made me content to just live with a little whine.
My TC had harsh buzzing from 30-50 mph. Also a bit of whine at highway speeds. I also added 2 bottles of lubegard torque converter fix. So far so good a year later.
 

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Discussion Starter #9
Thanks habbyguy and Maguffin1995.

I know it's been a while but, I've been dealing with some other issues with the MDX. I'm going to try the triple drain and fill with Redline D4 and add Lubeguard Platinum on the last fill.

Any tips on this process? How many miles should I drive it with Redline D4 between each drain and refill?

Are there any posts outlining the steps to the transmission drain and refill for the '06 MDX? I imagine it's pretty straight forward.

How much fluid is required for each fill?

Thanks for any and all help.
 

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Discussion Starter #10
Would running some Seafoam through the transmission prior to the drain and fill help clean it out?
 

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Wouldn't recommend Seafoam in a tranny, but you might find some who think it's a good idea (I wouldn't but I also wouldn't have trouble believing that it might work).

I'd do the Redline drain and fill and drive a day or two, and then again, and once more, with the LubeGard Platinum finisher. The D-N-F's are easier than an oil change. Just pull the plug until it stops flowing, and put in as much fluid as came out. I find it easier to use a long, skinny funnel (or hose connected to a funnel) into the dipstick hole than to be bothered removing the fill plug, but YMMV, of course.
 

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Discussion Starter #12
I bought 3 gallons of Redline D4 ATF and a bottle of Lubeguard Platinum. I hope to find time to do a couple drain/fill cycles this weekend. After I get it done 3 times and add the Lubeguard on the last fill, I'll report my results here.
 

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Discussion Starter #13
I drained and filled the ATF 3 times as recommended using Redline D4 and including Lubeguard Platinum on the last fill. The whine (dental drill) sound remains. I do think it's somewhat reduced.

Oddly, and this could just be the difficulty with remembering sounds, I think the reduction in the whine occurred after the first drain/fill cycle. It may have improved slightly with the subsequent drain/fills and the additive but, I can't tell. It may have actually gotten slightly louder after the 2nd and 3rd iterations.

I'm disappointed to still hear the whine but, I may try some Lubequard torque converter fix. I would just need to drain out an equivalent amount of fluid.

So, here's something odd. After getting this done yesterday I get in it this morning and the battery is dead. Coincidence? Seems pretty crazy but, the battery is a few years old. I've just never had one go from fine to dead without any warning. Yesterday, it was fine while test driving, etc., after the last fill. I did spill some ATF onto a wire loom that runs near the fill hole. I'm wondering if the ATF fluid shorted something and drained the battery. Thoughts?
 

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I wouldn't get too excited about draining any fluid when adding the shudder fix (it's a small tube). Too bad that the whine wasn't reduced more.

FWIW, my plan was to pull up the front carpet and put down some sound-deadening product (in my case, this would have been underlayment for wood floors, since I had some of it on hand, and it worked amazingly well on my motorhome, where I'm sitting directly above a V8). I figured I'd pull the carpet out as much as I could without totally removing the console, etc., and put down layers of the stuff where I could reach it. I'm 90% sure that the sound in the cockpit is traveling to the firewall / footwell walls through the air, rather than being coupled in through the motor / tranny mounts. I could be wrong.

And here in Arizona, a battery that's a few years old is always suspect. It's always possible that something was left on after you worked on the car - I'd get that battery tested just to find out if it's in need of replacement, and then see what happens.
 

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Re the battery, if you can get it jump started, check voltage across the terminals to see if your getting 14.x volts. If not your connections could be suspect or the alternator could be starting to fail.

Make sure your connections at the battery are good, not corroded. If you’re getting the 14V, your battery could be going. Check/add fluid level and a test at the auto parts store as Habby suggests. I’ve been getting Costco batteries and it seems they last 3-4 years, sometimes 5.

If the X sits often, you might want to get a 2A charger with a maintainer - probably $30-$40 at Harbor Freight or Walmart.

Good luck!
 

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Discussion Starter #16
Thanks habbyguy. The shudder fix being a small amount is good news. It's amazing how much ATF got everywhere as cautious as I was.

At noon, I ran home and the charger showed the battery fully charged. I disconnected it and started the MDX with no issue. I drove it to the office this PM. We'll see how it goes.

I keep a log in vehicles where I record all maintenance. Last night, I entered the ATF drain and fill + Lubeguard. I did turn on the ignition from the passenger side to see the mileage and wonder if somehow, being old and worn, it didn't actually get shut off correctly. It's the only thing, other than spilling ATF or an incredible coincidence, I can think of. Again, we'll see.

By the way, on the way back to work I turned off the radio. Maybe it's my imagination or I was highly tuned to the whine yesterday but, it seems markedly improved relative to before the fluid changes. I'll throw in the shudder fix and try to avoid the sound insulation! It never really was that bad and the radio is always on regardless.

Thanks again.
 

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Discussion Starter #17
Thanks LOP.

Yeah, the terminals are very clean and the battery took a charge OK. My charger has some analytics and it says things are OK. Battery voltage and alternator output both look good. I really do think something weird happened when I turned it on to get the mileage. When I walked away the headlights remained on and that seemed odd but, I wasn't really sure what the behavior should be when just clicking the ignition on and then back off.

Oh well, first world problems, I like to say. My gal's sister manages a Batteries Plus store so, I get pretty good deals on Duracell batteries. If the battery is shot, about $75 will take care of it.
 

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My personal philosophy of car art allows me to thoroughly ignore one instance of bad behavior by one of my cars. I just assume that it was a glitch that will never, ever happen again. It could have been something as "simple" as a sticky headlight relay in your case (that happens). Just keep your eyes on the shut-off behavior and if there is still an intermittent problem, it'll show up eventually.

Here in Arizona, the heat kills just about all batteries in 2-3 years. I normally get one free (or free-ish) replacement on my batteries, as I know to buy batteries with warranties that extend beyond the "AZ lifespan".

And glad to hear that it sounds like the whine has diminished - that was my perception as well. Every time I did a fluid drain-and-fill, the whine would decrease noticeably. It was always there, but never really reached a "problem stage". I was to the point I was going to try tracing the sound from the transmission to the cockpit, but got rid of the car before I could do that. My best guess was that it was coming through the firewall, and that sound insulation under the front carpet would make a big difference (high frequencies just don't get through that stuff easily).
 

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Discussion Starter #19
Agreed habbyguy. This vehicle owes me nothing. I've owned since new, 13 years and counting, and it has never failed. Not once. Well, I guess you could say the dead battery is a failure but, most likely is a fluke or, it's time for a new battery. Anyway, I'll be watching it as the colder weather here in MI will precipitate any battery issues quickly.

The whine is appreciably better and just knowing it's characteristic and not imminent failure, it's not loud enough to bother me. The radio drowns it out. I feel better knowing the fluid change is done and the vehicle, setting aside a potential battery issue, is solid again and good to go for the winter. I park my other car and start driving the MDX around the end of November.

Thanks again for all of your feedback and assistance. I really do appreciate it.
 

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Discussion Starter #20
So, get this. I have found what is either a bug in the firmware of the MDX or, some anomaly in my particular vehicle. With the vehicle off and sitting in the garage for hours, if I open the passenger front door, turn the key on long enough for the headlights to come on, then turn it off, pull the keys from the ignition, and close the door, the headlights remain on indefinitely. Well, actually, until the battery dies.

While sitting with the headlights on, if I walk around and open the drivers' side door, the headlights go off.

Very strange behavior but, explains what happened to my battery on Monday. I had opened the passenger door and switched the key on to read the mileage to make a service log entry. When I walked back into the house, the headlights still being on caught my attention but then, I just thought, they'll go off. Apparently, they don't.
 
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