Lexus GS 300 3GR-FSE Automatic

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Re: Lexus GS 300 3GR-FSE Automatic

Post by Martyn » Tue Feb 07, 2017 11:08 am

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Re: Lexus GS 300 3GR-FSE Automatic

Post by volrem » Tue Feb 07, 2017 6:39 pm

I would measure vibration inside cabin first because this is were you feel it. Lot of vibrations are under the car that may not be felt in cabin. Would like to know how much of that vibration is in cabin.

However it's clear that you have P1 vibration. So either propshaft or something that rotates at the same speed. Looking at vibration level i would look at propshaft first.

If you have optical sensor kit the you could do propshaft balancing yourself.

Or just install hose clamp and road test, move clamp around and see if it changes.

Have seen many propshafts that have been "balanced".

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Re: Lexus GS 300 3GR-FSE Automatic

Post by Steve Smith » Tue Feb 07, 2017 9:16 pm

Hello Martyn and thank you to all for the posts.

Sorry for the late reply and thank you for the cover Kev, STC and Volrem

This is a fantastic example vehicle and will make for great case study as we proceed through the diagnosis.

The fact we have been able to test the vehicle on the road with the customer is perfect.

This way we are all talking about the same vibration. (A customer willing to co-operate too is a joy)

Using the 90 kmt file, what is clear to see is that we have a P1 or NEAR P1 vibration that is road speed related and affecting the vehicle predominately in the vertical axis at the differential.

The accelerometer mounted on the centre bearing returns very little amplitude at the P1 frequency and so it would appear we are in the sweet spot of vibration with our diff mounted accelerometer.

Can we assume that the peak around P1 is present when the customer can feel the vibration?

Why I have mentioned NEAR P1 is the fact that at times the P1 indicator is not fixed at peak amplitude. See the image below
Unknown adjacent to P1
I suspect we have another gear ratio to add too (possibly 6 speed auto?)

I say this is because using OBD to obtain road speed, propshaft speed / frequency is calculated by multiplying T1 by the differential ratio. 3.73:1

For example T1 is 13.1 Hz at 94 km/h x 3.73 = 48.86 Hz (P1 is displayed at 49 Hz)

However when using the “Calculate Road speed” method
E1 at 27.9 Hz / 5th gear ratio (0.719) = 38.80 Hz. (This cannot be right)

What I would like you to do here Martyn is to invite the customer back for another road test only this time use the "Calculate Road Speed Option". See image below
Calculate road speed
This feature will utilize engine speed and selected transmission ratio to calculate road and propshaft speed.

You will need to inform the software of the gear selected by the driver (manually shifting the auto box) under the signal history See image below
Select the relevant gear
What I hope to see is a possible separation of P1 and an unknown vibration in close proximity.
Could you also remove the front differential final drive values from the Advanced Vehicle information?
Advanced settings.jpg
Remove front diff and add missing ratios
Whilst the values should be ignored for RWD settings I think it best they are removed. (Set to zero).

Can we confirm our transmission and differential ratios are also correct?

I can obtain these for you if required? (I suspect we have a 6th gear ratio missing)

During the road test when the vibration is present can you downshift to a lower gear whilst maintaining road speed?
Note the effects on P1 or vibrations in close proximity to?

Could you then try to maintain road speed whilst selecting Neutral (not easy I know).
Could you again note the effects on P1 and other neighbouring vibrations?

Should P1 or vibrations nearby remain high, we most certainly have a road speed related vibration

If they fall substantially we have engine related vibrations present at a similar frequency to P1

Given we know the vibration sweet spot is around the rear differential, can we position our second accelerometer ( in the vertical axis) around the rear subframe adjacent to the drive shafts.

My line of thinking is we can “zone in” on a rear left or rear right P1 style vibration.

If we can faithfully reproduce this vibration on a hoist with the suspension compressed as though on the road, can we run the test again with the rear wheels removed? (Disable TRC)

This will remove the influences of wheel imbalance and load upon the drive train.
If our vibration remains evident, can we then disconnect the drive shafts?

Think of a drive shaft with CV joint generating a “T” order vibration.

There is a lot above to think on Martin but we are here to help.
I will be off site for a few days but will try to check in on my travels.

I hope some of the above helps. Take care. Steve.

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Re: Lexus GS 300 3GR-FSE Automatic

Post by PicoKev » Tue Feb 07, 2017 11:00 pm

Crikey Steve that is a beast of a post to construct on aeroplanes and in airports! 8) 8) ]

Martyn, I hope you think it was worth waiting for Steve to reply. :wink:

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Re: Lexus GS 300 3GR-FSE Automatic

Post by Martinjensen » Wed Feb 08, 2017 8:32 am

Hello Volrem, and Steve.

@ Volrem.
Thank you for ansvering.
In my first post, there is a recording labeled "høj fart" (High speed in Danish) - Yes i know the meaning of the Word fart i English - I am now more aware of choosing filenames, to be shared on a international forum :-)
- The reason for mounting sensors on the diff and center bearing. is because of the high P1. And the vehicle repair history, with damage to the pinion bearing.

I do not have the optical sensor kit, but i think the imbalamce is too strong to try to correct, by balancing.

@ Steve.
Thank you for the detailed ansver.
Im am still learning my new Tool, and this is a great case for learning.
I have made som errors, regarding the gear ratios.
The ratios for the gears is from a previos car, and is is my fault that i dident errased them. (I would prefer if the software removes previos indputs, vhen we select new Measurement in the initial screen)
The car have a 6 Speed Automatic, and i cannot find the specs for ratios (I have full acces to Lexus puplications, but cannot find them)
The Gearbox code is A960E
The rear diff ratio is: 3,727
i belive the vibration is a P1. But i cannot figure out what the vibration is that is occurring just above P2.
The P1 vibration is present when the customer is experincing the vibration.
During the road test he is not allowed to look at my computer (To aviod a Placebo effect) And when he informs me of the presense of his concern, is matches the groving P1 amplitude.

I was thinking based of what i've measured, that there must be somthing wrong with the propshaft, given the fact that there are a strong P1, and the pinion bearing on the old diff failed.

That lead me to measure the vibration leavels on the gearbox output flange, the center bearing, and the diff.
The vibration is verry high on the rear diff, and almost gone at the gearbox and center bearing.
The propshaft is monted in the center bearing via flexible rubber, so i beleve that a direct comparison is not possible. But given the fact that the vibration is so high on the rear diff, and the fact that the diff is relative new, and was replaced do to pinion bearing fault. There must be a problem with the propshaft.
Upon closer inspection of the rear section of the propshaft, it became clear that the driveflanges is alike, so i removed the rear section of the propshaft and turned it around front to back, thinking that if it was infact a propshaft problem, i should be able to move the vibration from the diff and to the center bearing.

This lead to a reduction of the vibrations by 2/3 of the level at 72kmt.
And also a reduction of the vibration at 90kmt.

The car also accellerates mutch smoother, and the customer confirmes that the vibration levels has dropt.

In the rear section of the propshaft, the Yoke is vulcanized on the propshaft tubing, and the guy that had balanched the propshaft velded veight to the propshaft in this location. I dont think that it is a great idea to heat this rubber.

The customer will now present our Measurement and findings to the dealer, to see if they are willing to replace the propshaft
efter 90kmt.pddata
After propshaft rotation 90kmt
(640.97 KiB) Downloaded 101 times
Efter 72kmt.pddata
After propshaft rotation 72kmt
(596.05 KiB) Downloaded 96 times
2017-02-08 09_24_54-Rear propeller shaft assembly components.pdf - Adobe Acrobat Reader DC.png
Vulkanized section

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Re: Lexus GS 300 3GR-FSE Automatic

Post by Steve Smith » Thu Feb 09, 2017 12:15 pm

Hi Martyn, nice work and good diagnostic procedure.

I have noted and reported your suggestion surrounding the "Start a new test" option in the NVH software should mean exactly that and not include any previous vehicle details.

Looking again at the latest 90 kmt file your P1/Near P1 has reduced dramatically from approx 126 mg to 44 mg and this provides undeniable objective results for your costumer and for you as a technician.

Often with vibration diagnosis it is very difficult to asses whether we have made an improvement based on our senses alone. (you rightly mentioned the Placebo effect) This is a typical case as a vibration remains but far improved. (confirmed also by the customer)

The fact we have "before and after" test results confirms we are moving in the right direction and I would be keen to see how this develops between the customer and the sales team from where he purchased the vehicle. Can you feedback when possible?

If a new propshaft is not installed then I would like to try the propshaft balance option within Pico Diagnostics using the hose clamp method.

I am sure we can reduce this vibration further in order to provide more evidence of propshaft failure (if applicable)
Such an option continues the diagnosis process without unnecessary parts replacement.

I have to say Martyn that your T1, T2 and T3 are all considerably high in the latest 90 kmt. (approx 30 mg at 90 km/h)
I think we should monitor this also as we reduce P1. A reduction of P1 combined with our T vibrations should restore this vehicle to its full glory.

The ratios required are as follows

1st 3.538
2nd 2.060
3rd 1.404
4th 1.000
5th 0.713
6th 0.582
Reverse 3.168

These can be found on the Lexus site under New Car Features (NCF)

I hope this helps, take care.......Steve

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Re: Lexus GS 300 3GR-FSE Automatic

Post by Martinjensen » Thu Feb 09, 2017 2:28 pm

Hello Again Steve.

And thank you for the continued feedback.

I also have concerns of the elovated T vibrations.
And this is leading to the question, can a strong propshaft vibration cause T vibrations, as they are directley linked via the diff??

I will post more feedback as this case progresses, the reason for contacting the dealer at this point, is that they have stated that the car is fixed. Now we have evidence that this is not the case. And we have providet some direction for them to go, if they will look at the car Again.

Nether way, i will have the car back, for a after repair capture, or a continued diagnostic.

Thanks for the ratios, i will use them in the Next recordings, I was looking in the repair section of Lexus puplications

Regards Martin

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Re: Lexus GS 300 3GR-FSE Automatic

Post by Steve Smith » Tue Feb 14, 2017 11:59 am

Hi Martin re your question
“Can a strong propshaft vibration cause T vibrations, as they are directly linked via the diff??”

A vibrating component will generate vibrations that can be felt through the entire vehicle (all be it at different amplitudes in different vehicle locations)

What is key to identifying the vibration is the frequency.
Let’s take your P1 vibration 49 Hz, this will be at 49 Hz throughout the vehicle and so assists the technician it is a component rotating at propshaft speed (Hopefully the propshaft)

Let’s now assume you have a differential ratio of 3:1 and we have a high T3 vibration, T3 and P1 will vibrate at the same frequency and so combine to increase the amplitude recorded at this point in the spectrum

To clarify the above:
P1 50 Hz / 3:1 diff ratio = 16.66 Hz which will be your tyre frequency (T1)

Assume now we have a 3rd order tyre vibration (T3)
T3 = T1 x 3 = 16.66 Hz x 3 = 49.99 Hz which is identical to P1.

Here we have P1 and T3 combining to increase the recorded amplitude at 50 Hz

The software would however indicate T3 and P1 within the recorded peak at 50 Hz which should assist with the diagnosis

The same can be said when balancing a propshaft with the transmission in a gear ratio of 1:1

In this scenario we have E1 and P1 at the same frequencies and so any engine vibrations at E1 will combine with vibrations at P1

To avoid such confusion balance the propshaft in another gear ratio than 1:1 and be aware of the characteristics of diff ratios at 3:1 if a high T3 is captured

I hope this helps, take care…….Steve

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Re: Lexus GS 300 3GR-FSE Automatic

Post by Martinjensen » Thu Mar 09, 2017 10:45 am

The Lexus is back :-)

My customer presented the dealer with the Measurements we had made, and they agreed to pay for a new genuine propshaft for the car.

The propshaft is now installed on the vehicle, and angles measured Again.

A after repair capture confirmes that the propshaft speed related vibrations has dropped drastically, and the customer is werry pleased with the car Again.

There are still som Tire speed related vibrations, and we did confirm that the left front tire has a high road force.
The car is on Winter tires right now, so when summer comes the tires can be replaced :-)

Does anyone know of some NVH training classes i can attend ?
160kmh 100mph.pddata
After repair capture 160kmh / 100mph
(862.5 KiB) Downloaded 107 times
After repair capture Screen shot 160kmh / 100mph
Old prop with non original balancing weight welded to it
New prop.PNG
New genuine Propshaft

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Re: Lexus GS 300 3GR-FSE Automatic

Post by Steve Smith » Fri Mar 10, 2017 9:07 am

Hello Martin and thank you for taking the time to feedback and bring this one to a close.

Hats off to you my friend for tackling this one and providing your customer with objective test results that have brought about a conclusion.

For NVH training, could you contact our distributor in your market place?

This would be Autotek. You can find their details by searching for your local distributor on the Pico Auto Website.

Your contact there would be Klaus who is a great guy with hands on experience with NVH
You would looking to take Step 5 in the 5 Steps To Success training program

Let me know how you get on

Take care.......Steve

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