Hi all,
Not too long ago, I heard a low humming noise when accelerating while above 60-65mph. This morning going to work, I heard a grinding noise in the front at low speed. WTH??? The noise sounded like your brake rotor resurface. Only happened at low speed, maybe due to too much noise and can't hear it at higher speed. The low humming and the grinding noise both happened when I accelerating under 2k rpm. On my way home, was only able to duplicated once while morning was happening constantly. Talked to my service advisor about the humming noise and they said their technician can only be driven no more than 65mph. So that's is almost out of the picture. Scheduled an appointment sometime next month (no loaner until then) for the grinding noise.

Been reading the forum, noticed some has issue with their trans/diff case, but all on type S. Mine is a 23 aspec awd, with a little over 7k miles.

Has anyone experienced this or similar to it? No error code or show any symptoms other than the noise.

 

Have you tried to see if you are getting power to the rear wheels by putting it on jackstands or a lift and put it drive to see if all wheels spin. I'm wondering if your transfercase splines stripped out like mine did. When my transfercase let go I didn't hear any loud noises I just noticed I was getting low traction and the car behaved as though it was a FWD car, lots of wheel spin and torque steer

 

i think most if not all transfer case fails situations were on a 21 and limited to type-s if im not mistaken

 

I think i saw your post before. I have not test this yet. Not enough jackstands at home lol.
I did noticed the sh awd display on rear wheels only showed 1 bar when I hard accelerating (already at 60mph+) while curving. This is where on the freeway merger (one particular spot I usually go on weekend) I usually when I hit the gas on the curve and can see my awd display showed the rear wheels has more bars to one of the rear wheel. This time it just stayed 1 bar, and only the front showed. I don't know how to get acura tech to replicate this.

 

when i had my transfercase/transmission issue when i lost power to the rear wheels the car threw no codes and rhe dash said it was sending power to the back even though it wasn't. So you really can't depend on the display for trouble shooting.... I noticed it when I was pulling out of my street in the rain and when I fed it throttle and all the car did was boil the front tires.

 

Thanks vette! I already scheduled for a visit next week. Pretty sure they'll come back with nothing wrong with the car and we can't drive the car past 65 to test anything lol. I'll ask them to lift it up and put it in drive and see

 

They shouldnt need to test drive it to see if the AWD system is faulty... they only need to put it on a lift and put it in drive to see if the rear tires are getting power.

 

Went to the dealer, and they came back with no issue...said honda awd is not design to be awd all the time, but awd only activated base on road conditions..I said awd supposed to be awd all the time, maybe power distribution differently but supposed to be on all the time and dealer said no it not how it's supposed to be.

I asked them to put on the lift and see if rear wheel spin or not, they refused and said that's not how it work...am I wrong on this awd?

 

No i'm pretty sure you're right. I believe from low speeds, it sends power to all wheels equally. But then at high speeds, it sends most of it to the front for fuel economy. But, a little bit is still sent to the rear. I'm not sure why they're telling you differently.


^Shows a good demonstration as to what they should see when they put it up on the lift.

 

Thanks for the video. I have seen it before and assuming that's how it is but according the the dealer's tech and sa, I'm wrong.
This is what I got from their print out and also found an article online explaining acura's awd system :"During normal operation the clutches were disengaged, allowing the rear axles to freewheel, delivering all engine power to the front wheels".

Is this mean if there's no accelerating, the rear shouldnt be spinning at all? If so, the video above showed otherwise. Should I even take this up with hq or forget it? If I let this go, how do I tell if my awd is even working properly? It does felt differently after the "pop" I heard comparing to when I first got the car.... :/

 

Simple - put your car on jack stands and put it in drive like in the video. If you don’t have the resources, take it to a shop and ask them to put it on a lift and raise it up slightly. Even without resistance, all 4 wheels should be turning. I would not let this go even if the service order you got from your dealer states otherwise; misdiagnosis can and do happen.

 

Your dealership is retarded. Tell them you'll be taking your business to a different dealer and writing a nice review for them on google and other places - see how fast they will be like "oh yeah your transfer case needs to be replaced but don't worry my man it's all covered under warranty <3" - essentially what I did with my dealership where I bought the car, they begged me to come back and that they will take care of me but I told them they can go f themselves and I serviced my car at a much better place.

 

Thanks all for the tips. I'm going to see if I can borrow a few jackstands and do this test, or pay a small fee at mom n pop shop to get the car lifted and see what's going on. I'll be writing to hq as well and see what they say.

 

if you can get under and record some video, that will be your proof. If your driveshaft is not turning while in drive and having the car lifted; then it will be evident you have a mechanical issue hence the possibility of the splines being stripped between your transfer case and transmission. Keep us posted with your progress.

 

Well, had a quick chat with acura support earlier today. The initial response was the dealer was right, acura sh awd is NOT a full time all wheel drive, rear wheels only activated at certain conditions. I then told the representative that my understanding between 4wd and awd and the way acura told me is pretty much it is a 4wd system and not awd. I also asked about those videos online people demonstrating acura's awd where all wheel spinning at the same time while in D on the lift, and according to acura statement, those cars are the one with problem then? I was told this will need to get escalated higher up and will get back with me with more info from their engineering team.

hopefully I can get some jackstands and test this damn thing lol

 

The SH-AWD system is a front-biased AWD system (despite what Acura claims) where almost all the power goes to the front wheels until it needs to send traction to the rear (based on the steering angle, yaw sensors, loss of traction up front, etc). However, there's always a little bit of power that'll go to the rear wheels. It's never 100% disconnected. With the wheels off the ground and no resistance, even at idle that'll be enough to get all four wheels to turn. It's a more advanced on-demand system; by no means is it full-time AWD (like Subaru) nor is it a simple slip-n-grip system like most other basic AWD setups. And it's most definitely not 4WD.

 

OP, I am hearing that the MDX is starting to show a similar issue and it is the transfer case spline being stripped which results in power not being sent to the rear wheels so if you do end up noticing an issue and keep hearing noises it may be a good place to start.

 

Thanks fiatlux...unfortunately I will have to wait until acura get back with me on this. Haven't been able to get it lift up yet to see if back wheels are spinning, crazy weekend lol. I did made an appointment with a different acura dealer and see if they can do anything. I will see if I can get a gm or district manager out and have a chit chat with him/her. This is 3 weeks away


Thanks for this info. Not good for acura if they starting to fail on the awd. I did noticed a new, different noise two nights ago when I drove home in the middle of the night. Sound like ball bearing gone bad, but only at low speed and low acceleration. I tried to duplicate this during day time but can't hear it, probably due to noises from other cars driving around. For sure happening at night when it dead quiet. Ha, this should be easy telling the service advisor n tech on that lol

 

The sad thing is Acura has been producing SHAWD cars for well over 15 years and I've never heard of this failure until recently. What are they doing differently now.

 

I imagine a good part of that is because Acura never had any cars with this level of torque output before. The old systems only had to handle something like 260ft-lb of torque. This Type S has almost 100 ft-lb more.

 

but what about the base TLX, base MDX and base RDX that are having transfercase issues. Seems like bad metallurgy or something if the output splines are stripping off. I have heard of civic guys converting their turbo civics to AWD using 80's AWD wago transfercase and rear differentials and making serious drag cars. So how could Honda overbuild their old cars to handle the power those guys are putting through them which is WAY above and beyond what the original Wago was even thought to make, and the modern cars can't even handle the stock power.

 

Best guess is the current gen transmission design saved weight & cost and thus how the transfer case meets up with the transmission (via this spline) seems to be a weak point.

 

Man, reading this thread ... just makes me sad. Glad I never got answers like that taking my cars to Honda and Acura (all bought brand-new and always Dealer Serviced where we bought them).

If you ever decide to trade it away ... at least drop by an Audi dealer and take a test-drive in a loaded A5 or S5. Mine is like a AWD rocket off the line ... dirty road, gravel, rainy, even snow and ice. Feels very safe even at high-speeds.
For a little-more you can get a RS5 or a Porsche.

 

Well, there is my buddy Fiatlux .

Yeah, but I thought the transmission and drive-train in the Type-S was supposedly upgraded to handle the extra torque, no?

 

well, yes but no lol

 

Lol I'll skip the audi brand. Never a German brand fan. I emailed acura client 5 days ago, no reply yet. I haven't able to do any testing yet. Been tempted to leave a nasty review on the dealership but everyone else there beside the damn sa guy was nice to me lol.

Would 4 2t jackstands be safe to use on the tlx? I think I can get 4 of those and maybe have a floor jack sitting in front for extra support?

 

Yah, the TLX doesn't weigh 8000lbs.

 

lol thanks 7057!

 

Four 2-3ton jackstands will easily support your car

 

From what a few friends (that are engineers) have told me, the issue could be caused by a few issues:

1. too much play between the splines and that is causing excessive wear
2. Out of balance shaft (like cars with RWD encounter)
2. Not enough engagement between splines (not deep enough, design issue)
3. Bad heat treatment (or treatment specs) for the splines (perhaps both male and female ends)

I'm very curious how how acura handles this as the MDX is a heavy SUV (more so than the TLX) and should have many more reports of this issue.

 

Well, AFAIK ... AudiUSA is an American company, and has been be like over 50 years. Sounds like a viable American company to me. They just make cars (no motor-cycles or airplanes).
https://media.audiusa.com/company-information

At my Audi-Dealership, service-inspections and work are video-recorded and posted online for me to watch. We can also text-chat with Technician (and of course Service Advisor) during work.
German like in no BMWs either ? How about Toyota and Mazda?
No. That does NOT sound safe, especially if rev-ing it up fast. I've always seen it done on a proper hydraulic shop auto-lift.

 

It's fairly obvious he was talking about Audi being a German brand. And no Audi is manufactured in the US, So AudiUSA is just a US representative import company for the US dealerships to German parent Audi which is a VAG subsidiary.
Where Audi's are made at 13 production facilities in 10 countries.
https://allamerican.org/investigation/audi/

 

Yes, Four 2ton stands would be fine

+1 I'm a engineer (although electrical/computer ) but since I've never read of any other MDX/TLX half shaft spline failures I doubt this is not a systematic problem. CV joint housing are extremely hardened especially where the spline shafts are, try using a center punch on one to mark it. It will dent the center punch. Perhaps the subcontractor for the CV didn't properly heat treatment with induction heating this particular shaft.

 

I still say Launching-Risk is too high for just a little test.
I had it done with the Maxima on a proper-lift and it's pretty intense.
Nothing you want to be jacking-around with on your nice un-damaged car.

 

that's what I am afraid of. Never did this before so was a bit iffy lol.
I got nothing against german brand like audi, bmw, etc...I just prefer something low cost for maintenance and something last long lol. Although my last 2 honda, one is 13 accord and the other is 16 tlx, both had major engine oil burning issue. Ended up trading in the tlx for the new one (I guess I don't learn lol).

Just a quick update, I am still waiting for acura to get back to me. Chatted with one of them earlier today to see why nobody get in touch with me yet. and they said they're still looking into my situation. What's shocking was I was told i may or may not get an answer from them at all. One of the reason was the awd information could be proprietary info....I didn't bother continue with the conversation after that and just hope they contact me later.

I ended up calling the gm at my dealership, and i asked the same question, whether my car is a full time awd or part time. His initial answered after a quick look up was it is a full time awd. He was not 100% sure but offered to get me back in and try to make this right. He's asking me to bring back the car and setup with a different advisor, will get the car lift up and check everything.

 

It can't be full time AWD because the TLX is a FWD-biased car w/o a center differential. Per the Acura website:

"To enhance both handling and stability, SH-AWD® can send up to 70% of engine torque to the rear wheels and actively distribute up to 100% of that torque to a single left or right wheel. This is achieved by routing the power generated by the vehicle's engine to a transaxle, while power is sent to the rear wheels through a torque transfer unit mounted up front rather than a traditional center differential."

https://acuranews.com/en-US/releases...20differential.

 

Yes, that is what the initial advisor told me. But if this is a part time awd, what does that mean? The rear wheel only activated at certain conditions, otherwise onlynthe 2 front are spinning? If so, how can they explain that whenever I let go of the brake, awd power indicator in my screen show all 4 getting power, and how to explain videos out there with their car on the lift, in Drive, and all 4 wheels are spinning?
This is where I am confused and pissed off due to refuses of service. I heard strange noises out of nowhere, after that my awd power indicator wasn't showing what I used to see prior to that event, especially on places I often go to, and it felt different when cornering. Maybe it just all in my head, and I am completely wrong, but all I asked if they can check and see if all 4 wheels are spinning, and diagnose the weird sound. This is where I got told to go home.

 

The Honda/Acura SH-AWD system is full time all-wheel drive. Also, the way all-wheel drive works is if it senses the front wheel slipping it will direct more power to the rear wheels, thus if your car is up in the air with all four wheels off the ground it will interpret that as the front wheels spinning and will allow the rears to spin. I have done this with all my Acura all-wheel drive cars for various reasons. If the rears are not spinning it means there is a disconnect somewhere in the system from front to rear.

 

It's not quite full-time AWD. AWD is "enabled" permanently, but with the TTU instead of center diff it only sends power to the rears as necessary. It's largely a reactive system that at steady-state will default to 100% front and 0% rear. Hence it's not fullt-ime AWD.

 

Oh man I'm getting mixed answers between full and half time awd lol. I just dropped off my car at another dealer and sa said the same, the car is not full time awd, only activated when need to. I get the part that once the car is I steady motion, all power goes to the front, but sa said during launch, the rear wheels get power if it see some splitting, otherwise it shouldn't spin at all....but at least he made the request to have it check and see if all 4 are spinning while on the lift.
I'm guessing if it not a full time awd, then the power indicator is not true then? On a flat dry surface, as soon as I let go of the brake, I can see all 4 wheels has power to it. Either it false reading or the indicator meant something else lol.