ellpipsis6

greetings everyone....so i got the 2017 TLX SHAWD and im just wondering why and where the vibration is coming from, the vibrations occurs when im cruising on a steady pace (low speed - 60-70kmh)....and i noticed that whenever i cruise between 1400-1500rpm the vibration goes nuts and theres a humming noise coming from the engine(i think)...but if i go over 1500rpm the vibration goes away and the car drives smoothly.....also whenever i downshift using the paddle shifter, the car tend to move forward instead of slowing down....thanks in advance

TLX15

Hi and welcome. You are not alone. Both problems you mention are common within this community. In response to your queries:

The vibration seems to originate in the rear subframe, however, the fix released in a Technical Service Bulletin (TSB) only reduces the vibration, it does not eliminate it. Forum members have had varying degrees of success in reducing, again, not eliminating the problem with replacing the original equipment Eagle LS 2 tires, most often, with Michelins. Acura seems to have washed their hands of the issue, stating that the vibration is within normal operating limits, and that they never promised the absence of vibration.

The surge you feel when downshifting manually is related to the design of the clutch mechanism. In order to shift from 5th to 4th, a dog clutch is activated. This, unlike a friction clutch, requires precise rev matching before it can safely engage, thus initiating this downshift, instead of quickly slowing the vehicle, disengages the engine, allowing it to coast unchecked, while the engine increases revs to match the speed of the lower gear. It is helpful to apply light braking during such downshifts. I think another dog clutch is involved with the 8th to 7th gear downshift as well.

I hope this input will help you enjoy your new car. May it bring you many safe kilometers of motoring.

Tardym

Hi Ellpipsis6,

Welcome to our world ... LOL. You will find multiple answer to your problem in this forum. Unfortunately , like stated by TLX15, the vibration issue is common problem with the TLX. You should bring back the car to the dealer and see what they can do for you. At least one of the TSB is a fix for your vibration issue. It does not solve the problem but reduce it. ( TSB 16-057 Vibration Felt In Front Seats and Floor at Highway Speeds ). See with Acura and let us know what they are saying.

Thanks, Mickey

TheSlash

My car is in service, and it looks like they are changing engine mounts in addition to transmission software updates. I believe there were 2 updates. ( my car is 2015 TLX SH-AWD ). In my case it's nothing to do with my tires or alignment or speed. It comes down to lower RPM steady cruising around 1250 RPM ( 1200 -1500). When torque converter gets locked, you can feel the vibrations in the steering wheel, transmission, even pedals. They say it's normal to get that torque converter lock at low RPM cruising speeds, but it's not normal to get that much vibration. I have not noticed this problem before and I have around 30 k on this car.
I hope you were able to get this issue resolved.

TheSlash

Update:
My issue was resolved. Got my car back and after 4 transmission software updates ( plus one that was already done back in 2015), engine mounts replaced and few other things done to the car ( all listed in the Acura Service Bulletins). Happy to report that car has no vibrations anymore. It appears to be fixed. I'll have to test more, specially in the cold weather but it looks good. It drives like new.

rubbertramp

Hows your car behaving now. Was the issue completely resolved.

Tardym

Hi The Slash,

Still have vibrations, not as worst as before the TBS was applied but still have vibrations. Dealer refuse to do a transmission software update as he said the problem is not with the transmission.

Looking at flushing the car once and for all, waiting for my wife approval ... LOL Tha car only have 19K KM (About 12K miles).

Might go for the new 2022 Kia Stinger.

Thanks, Mickey

rubbertramp

I have a 2020 one thats 5 months old. Going to the dealer for the 3rd time this week trying to replicate the issue. I always had an eye for the Stinger. Since its our primary car, wife did not like the Stinger much. I wish I had gone with the Stinger though. The only issue with the Stinger is the fuel efficiency.