Torque converter? thicker ATF?

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5
Location
Canada
First post smile I have 2008 Rav4 4cyl 4WD Automatic with 47Km miles on it. Bought the vehicle used at 20K miles. At 30K miles, I deicde to change the ATF and replaced with correct amount of OEM WS fluid. I did 1 drain/refill. I like to keep my ATF clean; there was no real reason to do this change. At 35K miles, I did another drain/refill but this time Valvoline Maxlife ATF compatibile with WS. A few thousand miles later, I start hearing a slight whine/drone whenever I accelrate between 24 and 26 mph under slight load e.g. slight hill or moderately flat surface. If I take my foot off the accelerator the sound is gone. You can also hear the same noise if you decelerate but only for a seconds or two since it does not take long to pass from 26 to 24 mph. There is no noise at other speeds. Although this happened after putting in Valvoline Maxlife ATF, I do not want to blame this situation on the Valvoline. It was only after a few thousand miles and the transmission still had 50% WS ATF in the mix. I have since done another drain/refill with WS ATF (so we now have 25% Valvoline left in the system) and added LubeGuard 60902 ATF Protectant. Still no change. One thing that I have observed is that I will not hear the noise when I drive the engine cold for the first 2 minutes. Does this sound like a Torque converter issue? Would using a thicker ATF solve the problem? What ATF could I use? Of course, dealer says it's normal frown
 
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7,516
Location
FL, USA
I would take it to another dealer. Or have your dealer let you test drive a similar model and see if it makes the noise.
 

MolaKule

Staff member
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21,951
Location
Iowegia - USA
Quote:
A few thousand miles later, I start hearing a slight whine/drone whenever I accelrate between 24 and 26 mph under slight load e.g. slight hill or moderately flat surface. If I take my foot off the accelerator the sound is gone.
This could be the exhaust system, the differential (checked it lately?), or possibly the universal joint. If it has a center driveshaft "guide" bearing this could be the cause as well. Don't go messin' with the tranny until you have done some more diagnostics.
 
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lavaniol

Thread starter
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5
Location
Canada
My RAV was not making this noise before; so I know that it did not come from the factory with this noise. Transfer case and Rear Differential lube was changed twice in the past 2 years. So I know there is fresh lube in there. I took it to the dealer and they hear the noise when I drove it with them but said it was normal. What kind of diagnostics should be I get done? What kind of test should I get for the exhaust? Mr. Muffler looked at it and could not find any leaks. Took it to Mr. Transmission who also heard it but could not pin point what could be the problem."Come back when it gets worse". I took it to a local mechanic but could not reproduce it on the hoist. The thing is that the noise is not too loud but I drive 25 mph city 90% of the time and it gets annoying fast.
 
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9,559
Location
Boston, MA
Having owned a number of Toyota Camrys my only useful observation is that as milage increases the auto transmissions tend to work better with slightly thicker fluid, which may be what you get when it's cold. You might try a jug of Lucas stop slip, it's far from a cure all but it is is thicker than ATF and may make a difference you can hear. If so, I would suggest you ask the brain trust here for their thoughts on a thicker AFT, staying within the guidelines for your transmisssion of course. Not all AFT of the same type is EXACTLY the same thickness. One of my Camrys has 300K on it and still shifts fine so long as I do the fluid replacement of about 2.5 quarts every 25K. As far as doing a "full fluid exchange" the jury is stil out about that.
 
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17,909
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Silicon Valley
Does it sound the same if you coast between 24-26mph? As in not pushing on the gas pedal? What about in neutral and reving engine? If it is vehicle speed instead of engine speed, I'd say it is less likely to be exhaust, engine mount, etc but more like axles / shafts / tires / wheel balance etc. Also do you see any difference if you coast in neutral between 24-26 vs stay in drive? What about choosing different speed (i.e. not in D but in 2 or 1)? Does that change the speed it causes problem in?
 

MolaKule

Staff member
Messages
21,951
Location
Iowegia - USA
Quote:
You might try a jug of Lucas stop slip, it's far from a cure all but it is is thicker than ATF and may make a difference you can hear.
I would not put any of the Lucas thickening junk in it. Thicker lubes may only mask a potential problem. Toyota WS is about the same viscosity as DexronVI, MaxlIfe ATF, Amsoil ATL, and Redline D6, alllow viscosity ATFs. My experience has been that torque converter noise is most noticeable in idle and changes with engine speed. Are there any leaks or wetting around the drive train components? Panda Bear has some good suggestions as well.
 
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6,614
Location
southeast US
I also have RAV4 and can tell you the tranny is known to produce whine in the 3rd gen model. Especially the V6. I4 less commonly. It's considered harmless, even though toyota offered replaced tranny under warranty for the V6. You'll find a whole lot of more info on RAV4world.com. BTW, when I had the whine in mine (at 30 mph and then about 40 mph), I tried D4 ATF being much thicker. No change. I got a new and "improved" tranny. Now, 15,000 miles later, slight whine is audible at 30 mph. 99% drivers wouldn't notice. But I do notice things like that.
 
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2,393
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Paradise of Florida
It's normal whine until you can hear it 100' away. Turn up the stereo. Make sure that you are checking the level correctly...running vehicle, proper ATF temp, level surface.... If AWD, change the xfer case and rear diff lubes, and grease the ujoint fittings. If hydraulic PSF, which is another source of harmonics and whine, siphon refill several times.
 

lavaniol

Thread starter
Messages
5
Location
Canada
Originally Posted By: PandaBear
Does it sound the same if you coast between 24-26mph? As in not pushing on the gas pedal? What about in neutral and reving engine?
coasting at 24-26 does not make that sound. If you press the accelerator and keep the speed in the range, the sound is back. I am not able to reproduce that sound when in neutral and revving in my drivway. However, I don;t think I can hear anything on top of the regular noise. The RAV4 is a poorly soundproofed vehicle.
Originally Posted By: PandaBear
If it is vehicle speed instead of engine speed, I'd say it is less likely to be exhaust, engine mount, etc but more like axles / shafts / tires / wheel balance etc.
It does the same noise with my winter tires. So tires/wheel balance are less likely. My bet is engine RPM; taking foot off accelerator cancels the noise. I can't explain the decelration. May be torque converter mechanism? when decelerating, it feels like the whine/noise starts at 26 mph and stops at 24 mph as (it feels to me) the torque converter unlocks.
Originally Posted By: PandaBear
Also do you see any difference if you coast in neutral between 24-26 vs stay in drive? What about choosing different speed (i.e. not in D but in 2 or 1)? Does that change the speed it causes problem in?
I have tried putting the RAV in 1 and 2 before and did NOT notice any difference. I have not tried to switch the car from D to N when driving at that speed. I'll need to report back.
 

hpb

Messages
1,639
Location
Tasmania, Australia
Different car but same noise - my parents have an 08 Corolla, and from about 60,000km it started making a whining noise at dead on 38-40km/h. Exact same symptoms as yours, i.e., can't reproduce the sound on a hoist, or revving while stationary, etc. However, if you slip it from drive to neutral, the noise stops. To me, it sounded like diff noise. Long story short, he went to the local Toyota dealer and described it to the workshop foreman, who immediately said "Diff noise. Some have it, some don't. It will go forever and not get any worse, ignore it." It's now close to 100,000km, noise is just the same. Dad later told me he'd read something about the issue being crownwheels and pinions which weren't quite machined as matching pairs being the culprit. Possibly your issue?
 

lavaniol

Thread starter
Messages
5
Location
Canada
Thanks hpb. Seems like the same issue. The only thing is that the rear differential in my RAV4 got an extended "hidden" warranty from Toyota. But that can only be changed if the dealer admits that it is indeed the culprit. Otherwise, I have a warranty that I cannot use. Mine developed the issue over time so I suppose that it is just badly designed components. PandaBear, I switched to Neutral when the speed went from 26 to 24 mph. No noise. Of course, going from 24 to 26 mph has not noise as I have to take foot off the accelerator to switch from D to N. Greasymechtech: I will look into greasing the U-joint fittings, if that's possible on my RAV4.I know that those U-Joints cannot be replaced.
 

lavaniol

Thread starter
Messages
5
Location
Canada
FYI, I was referring to Toyota SPECIAL POLICY ADJUSTMENT WAB2190 for the "Rear Differential Coupling Sub-assembly PN 41303-42020"
 
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