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Discussion Starter #1
There have been serveral discussions on changing the transmission fluid, adding coolers (factory & after-market) and the fact that the X tranny does not have a filter of any kind.

The following link shows an inline filter that is available along with a cooler and hi-temp additive.

There are also sites showing add on filters that are basically spin-on engine oil types.

The additive by the way has been endorsed by Pat Goss more than once on Motorweek, for what that's worth. Probably a 'it can't hurt' kind of thing.
A key to adding a filter is knowing which
way the fluid flows.

http://www.txchange.com/ptk.htm
 

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At the expense of a long, boring post, with no direct connection to the MDX, and lots of pointless detail on Q45 transmissions, I am excerpting text from a conversation with a expert on transmission service:

Why Transmissions Fail
"Gil: Any trans that has a forward clutch that releases when 4th engages will have the problem of the rings shrinking or wearing out. Almost all the Japanese transmissions have this problem, and when it happens it is just as likely that the trans will come in with a planet failure, or forward clutch slip on startoff or during the shift to 3rd, or no 3rd hot or slip to 3rd. Dennis: Is there any one thing that you see as a reason why a major repair doesn't go as far as the original trans? Gil: If I can only name one it would be the radiator. Testing has shown that a high-miles radiator increases trans temperature 0 to 70 degrees. Dennis: Is this because the tubes slowly plug up? Gil:
No. Even with the tubes all open they don't transfer heat like a new one. They gradually scale up inside and out and the scale acts as an insulator. Dennis: Would sending the radiator out to be cleaned help it? Gil: Not enough to matter. The only fix is a new radiator or installing an ample size auxiliary cooler. Dennis: Does the higher temperature actually burn up the friction material? Gil: No. Mostly the higher temperature shrinks or deforms the rings and seals. Then the feed circuit leaks, allows slippage, which then burns up the friction units. Or ring crossleaks into or out of the lube circuit cause gear train burnup.
Dennis: So this would happen even if the vehicle got a brand new trans. Gil: Exactly, and it does. Dennis: Can you give an example of this? Gil: Yes. A Q45 is a great example. From new this car takes 4 people to Las Vegas from Orange County about once a week. On the Baker upgrade the converter unlocks, in 4th, and the trans temp goes to about 220ø .
If you took the trans apart you would find the end gap on the rear support rings is zero to 0.012". 4 years and 62,000 miles later the radiator is no longer new. And on one hot July day the temp goes to 240ø for about ten minutes. The rings now shrink and have a 0.035" gap. Feed for forward or coast crossleaks into the lube circuit and opposes the flow coming from the cooler. Soon there is little or no flow through the cooler. When trans temp gets to 280ø on a pull in fourth gear, the front planetary exits the trans. A major repair on the trans fails on the next hot trip. In fact, sometimes the job will eat the planet on the way home. Lots of shops have had this experience. After three repairs the owner is disgusted and goes to the dealer and buys a new trans. On the 2nd trip in July it burns up the planet. By this time somebody is more than willing to install a new radiator. What we say is: "install a big auxiliary multitube cooler for one fifth the money and 4 hours quicker."
Dennis: So what you are saying is that the higher fluid temperature doesn't burn up the trans
directly, but it causes ring and seal malfunctions that then cause the failure. Gil: That's it, and the solution is twofold. (1) reduce the fluid temperature by improving cooling, and (2) install rings and seals that can withstand higher temperatures and resist shrinking or deforming. Dennis: Is this why some shops pay up to $122 dollars for the original OE rings when repairing a RE4R01As, 2As, and 3As and some of the other Japanese transmissions? Gil: Yes. Those rings are a very special material and are literally bulletproof, provided the temperature stays within reason. But the shop should bear in mind that if the trans got hot enough to shrink the original rings, just like the Q45 did at least twice, the same new rings will also shrink unless serious cooling is added.

Personal experience: I fried two trans- now I installed an aux cooling radiator prior to the third.. Install yours BEFORE summer. No comments on additives- "Lubeguard" has been reported to help keep trans clean.

NOTE- It is NOT the fluid that breaks down at high temp, but the seals- so what does a hi-temp additive do to help?

Is this directly applicable to the MDX/Acura transmission? Don't know. Does it seem prudent? Yep

Ard
 

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Sorry, I should have been clearer:

I am using the Acura aux cooler on my MDX. (Long story, Acura paid for it, so what the heck.)

On my truck and on my Q45 I am using an aux cooler. (Ford Aux on the truck, towing a 10,000 lb gooseneck horse trailer.)

For the Q, I use a B&M 70268. I am not using the factory heat exchanger (which is built into the radiator). It has way too low a capacity (and after 7 years an uncertain interior cleanliness). The B&M has plenty of capacity. Costs ~$55.

Compared to the last rebuilt I put in at $2700, money well spent..

Ard
 

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Discussion Starter #5
I feel better now because I noticed on page 14-191 of the service manual, there is an inline ATF filter.
As near as I can tell it would only be replaced if the transmission was in for some repair, not regular maintenance.
Considering the transmission is not 'sealed' it had to have some kind of filter for particulates.
 

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I know high trans temp can "rapidly age" a transmission. For those of us not planning on towing [e.g. have NOT installed trailer hitch], I wonder if an aux. cooler will provide any benefit.

Does anyone know whether the MDX trans. has a tendancy to run hot? Have there been any trans problems that track to temp failure [I haven't seen any, then again, I don't think that there are many MDXs out there with 100,000 miles on them].
 

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Discussion Starter #7
You may want to do some more searches, there has been at least one case where the transmission temp. light came on during some degree of off-roading.
The driver pulled to the side, (as recommended by the owners manual) and allowed it to cool at idle, and the light went out shortly after.
I am having a full towing kit dealer installed, for the primary reason it will be warranted with the vehicle.
Although, there seems to be very few problems (at this point).
There are several after-market coolers that appear would be more effective than what Acura offers.
I don't plan regular towing, but like the capability plus the added margin.
 

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COST?

ANY IDEA OF COST TO HAVE THE DEALER INSTALL THE TRANS COOLER?
 

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Shooting from the hip, but is the "trans temp" indicator the actual drive transmission or the VTM-4 transmission?

I seem to recall that the indicator is for the VTM4, which would make sense that the repetitive lock-release-lock within the sealed, un-cooled transaxle might be exacerbated on off-road use.

Too lazy to look at the manual tonight.

A
 

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Discussion Starter #10
Both the ATX and VTM4 have temperature sensors. If the transmission overheats, it is indicated by the Trans Temp indicator on the dash.

The one from the VTM4 goes to the VTM4 controller. It likely disables the system in case of overheating to prevent self destruction of the rear differential.
 

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Re: COST?

paul123 said:
ANY IDEA OF COST TO HAVE THE DEALER INSTALL THE TRANS COOLER?
I asked around 6 months ago, my dealer said they won't install the OEM cooler that I bought from Tim! (Something about I didn't pay enough for it). I might take another run at it, show up cooler in hand while I'm getting my 30K service. Or break down and do the darn thing myself...

There quoted cooler+hitch was somewhere around $800.
 

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Ghost-

That kind of response sure make you want to give them your business, huh?

Just make an appointment for everything, and act dumb when you get there... If they say something: "Oh, I'm sorry, you are refusing to service my vehicle? Why?" I'd be surprised if Service cares what PArts made or didn't make on the purchase-

But then again, there is SOME competition locally- which motivates the different business units to be independent.

Dale-

Yes, there are two sensors- the ATF sensor will light the ATF dash indicator (controlled throught the PCM)(Powertrain Control Module). The VTM4 sensor will light the VTM4 light (but there is no "VTM4 Temp" light). No indication as to whether or not the VTM4, when it senses an overtemp condition, will disable nor whether it will signal the PCM to take any action.

The manual kind of casually states that the VTM4 light will come on "when you keep spinning the rear wheels while the vehicle is stuck..." But no direct comment on overheat.

BTW, there are two press in bushings on the rear diff subframe- anybody have a guess as to how long these will last? 60k or so? That's going to be a pricey service item...

Ard
 

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srpbep said:


Does anyone know whether the MDX trans. has a tendancy to run hot? Have there been any trans problems that track to temp failure [I haven't seen any, then again, I don't think that there are many MDXs out there with 100,000 miles on them].
Remember, one of the reasons that Acura requires a tranny and a power steering cooler is that the MDX tranny started to run hot. I don't remember the exact senario, but apparently, Acura was doing some hot weather testing in Tx. They measured increases in Tranny temps when they were towing in the Texas heat.

So, i would recommend u put in a tranny cooler on your 'X for reliability purposes. Specially, if you tow and live in my neck of the woods.

I am just trying to figure out which cooler to go with. Acura has told me that the transmission will not be warranteed if i put in a aftermarket cooler. The acura cooler sucks! So, i am thinking of waiting until 36K miles, and then placing a aftermarket cooler. the logic being that the tranny will only be out of warranty 12k miles earlier. If the tranny fails due to initial quality issues(bell teck), it should show up way before 36k miles.(I hope)
 

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Cooler?

MDXLuvr,

Guess I wasn't clear [sorry]. We don't have a hitch installed and don't plan on doing any towing. I was looking for info on need for improved trans cooling without towing entering the equation. Simply put, I understand that heat is a transmission's biggest enemy. Does the stock MDX have sufficient cooling for stock use [e.g. without towing]?
 

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Re: Cooler?

srpbep said:
Does the stock MDX have sufficient cooling for stock use [e.g. without towing]?
So you are asking if there is a design defect in the MDX as is?

I mean if the answer is anything other "yes" there is a problem with the MDX.

Now, since heat is ALWAYS the enemy of a trans, an aux cooler will ALWAYS help. You just can't say what is 'sufficient'. A cooler will add life in general- how long is sufficient? 100k? 150k? How many times will you get stuck in traffic at 110F? Just give more room for unusual condition.

Oh, Acura CANNOT simply void the warranty if you add an aftermraket transmission cooler, especially if you don't tow. They would need to 'prove' that the cooler caused the problem. In a case where the alternative would be 'no cooler' versus 'aftermarket cooler' they would be hard pressed. However, if you add an aftermarket, and tow, and the aftermarket is less effective, then they CAN void the warranty. Nevermind what the dealership says- talk to the factory rep.

Ard
 

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Ard,

While we are not going to do any towing, it does sound like you are suggesting that we might want to get the Acura trans cooler [one for the towing package]. Please confirm.

If yes, would love to answers to following:

(1) Is there an existing aux cooler present [replace with bigger] or is this a new install. I understand that there is a cooler built into the radiator [at least that is what I am used to].

(2) What does the aux trans cooler cost?

(3) While we're at it, I believe that the towing package also includes a pwr steering cooler. If this is correct, do you think this is needed if one has no intention of towing?

Thanks in advance ... Steven
 

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srpbep said:
Ard,

While we are not going to do any towing, it does sound like you are suggesting that we might want to get the Acura trans cooler [one for the towing package]. Please confirm.

If yes, would love to answers to following:

(1) Is there an existing aux cooler present [replace with bigger] or is this a new install. I understand that there is a cooler built into the radiator [at least that is what I am used to].

(2) What does the aux trans cooler cost?

(3) While we're at it, I believe that the towing package also includes a pwr steering cooler. If this is correct, do you think this is needed if one has no intention of towing?

Thanks in advance ... Steven
Yes, there is a aux cooler, and filter in the 'X. Acura just requires a larger one for towing.

The towing package costs in the $750-899 range. this includes tranny, and power steering coolers, trailer hitch, and the labor.
 

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anybody put in a aftermarket coooler on their MDX yet. I am trying to figure out which cooler best matches the MDX's tranny.
 

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Discussion Starter #20
You make your choices.......

There are thermostatically controlled coolers, which implies it's possible to 'overcool' the fluid. This would be the case during very cold spells.
The smaller coolers, including the Acura coolers, are small enough for that not to be a problem, while still providing additional cooling during warmer weather.
Other than that, I know of no specifications you could use to determine the best to use. Judge by overall dimensions of the unit, and adaptability of the hose fittings.
Understand the use of a non-Acura cooler 'could be' a bone of contention if there is transmisson failure. But this could go full in their face as you are allowed to use after-market parts. The Acura warranty should not be affected but that does not mean Acura will not try to 'weasel'.
Of course if the transmission failed as a result of the lines, and/or the cooler you connected leaking, you would be SOL.
It is the 'potential' problems, supported by the MDX's history of 'some' transmission problems, that keeps me from adding or changing anything.
I do use the factory towing kit including the coolers. While I think the factory unit leaves something to be desired, I think messing with coolers or using a different ATF fluid might actually help. But help what? Delay a potential problem? If it is going to fail, let it do it sooner not later, when it's out of warranty.
Do what makes you comfortable.
 
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