hwgray

I wonder whether any of you have had this problem. Occasionally' when the automatic is travelling at 35 mph and 1200 rpm, a vibration occurs which involves the whole vehicle. I can't predict when it will happen so can only show my mechanic now and again. Don't know whether it is the transmission or the automatic box. In all other ways, the car is superb. I remove the vibration be taking my foot off the accelerator.
Any advice would be gratefully received to explain the conundrum!!!

guzzy92fs

I experienced something similar and happened to be a bended wheel, actually all my wheels in my case
try to lift the wheels and spin them, check they are perfectly round.

hwgray

Thanks guzzy92fs
I will look into that. On the internet, I have seen that problems with torque convertors also do this so I will check that out too.

hwgray

guzzy92fs

Please keep us posted on your findings and hopefully a solution!

PC94

Is this issue similar to the one described in this thread?

https://www.clublexus.com/forums/gs-...ibrations.html

If so, there are dozens of other owners - myself included - with the same problem. I have yet to diagnose it, however, I suspect it could be a bad U-Joint, transmission mount, engine mount, or low transmission fluid levels.

Good luck!

hwgray

Hi guys, I told a transmission specialist what the problem was and he advised to have the transmission serviced with new oil and filter. I will keep you all posted.

PC94

Awesome, thanks for the update! Best of luck ... Looking forward to seeing what happens.

2013FSport

iTrader: (2)

Anyone care to sign up for a quick test?
It sounds like the transmission is going into torque converter lockup as in; the torque converter (T/C) is the fluid coupling connecting engine output to transmission input and the lockup section inside the T/C is a clutch in the torque converter that prevents slipping so as to reduce power loss from engine to trans and get us better fuel economy by reducing slippage. In short it acts like a manual transmison clutch and does not allow slippage.

However, if the load is too high for the engine it can present as bucking or roughness described here.

Two ways to test it... 1) a very very very light application of the brake pedal typically disengages the TCC (torque converter clutch solenoid). Try gently applying the brake while the bucking is happening. Does it go away?
If your brakes are being applied BEFORE the brake light comes on, the above test could be difficult. However, if the car thinks the brakes are applied BUT the actual brakes ARE NOT slowing the vehicle and the vibration stops, it is a very good sign that the problem is induced as a heavy load on the engine. Like having a manual trans car in 5th gear at 15mph and pressing on the gas. What will you feel??? Bucking..... Vibration.
You following me?

The next step would be to depress the switch which may NOT be just the brake light switch but another switch that is activated by the brake pedal.

Although this sounds easy it will be a challenge to depress the switch while in motion.
Options are, tape it down or adjust it so it activates before the physical brakes.

This is just a theory based on your description.
Try fuel system cleaner and better gas like 93 octane for a few tanks. Cleaning the MAF sensor may not be a bad idea if over 40k sense last cleaning.

2013FSport

iTrader: (2)

? Does this happen with a cold engine or only when warm? Or vice verse? Makes sense if it happens cold.
Does outside ambient temp matter?

hwgray

In Scotland, the summer temperature is between 10 and 30 degrees Cent (50 to 85 Farh). Makes no difference to the vibration. Thanks for the thought!

hwgray

Guys
I have had the automatic box serviced with new oil and filter and happily can report that 'my' vibration has completely disappeared. The mechanic said that the filter looked as if it needed to be replaced so, while I don't understand the mechanics/fluidics, the service appears to have solved my problem. Thank you for the suggestions and comments.
Have a nice day.

Harry

ibidu1

iTrader: (1)

Are you rwd or awd? How many km's are on it?

Have you inspected the wheels to see if there are any bends? A small bend in a wheel can be felt at low speeds and once you accelerate it could disappear. Also how are the condition of the tires? Are they wearing flat and even or are there any cupping or feathering?

designo

iTrader: (6)

Thank you for this info. I am experiencing this as well... always suspected tranny fluid.

hwgray

Hi ibidu1, thanks for comments. it is a rwd with 78 K on the clock. Wheels recently inspected when new tyres fitted. 35 PSI. I can confirm that the difference now with the transmission serviced is clear. I can see the change of the automatic gear coming at 30 to 35 mph and the rpm needle going down to 1200 without the shaking and vibration that was there for the last 6 months and getting gradually worse.

Levedis

Did the vibration go away immediately after you changed the fluids? Any other issues later with the tranny?