Piciu

Hi Guys,
Recently in my garage I've noticed some strange noises coming from the rear end of the car.
When I start rolling with wheels turned pretty much and slowly accelerating, there is some weird noise and small vibration, coming from rear right side. Once reaching around 15km/h (10mph), noise disappears. It's not clicking, it's like some clutch was slipping slightly (with used flywheel) and it gives some small vibrations.
- it only happens when going forward, not in reverse (with the same steering angle)
- it also happens when coming to a stop with wheel turned, just before stopping
- it comes from right side, does not matter which way steering wheel is turned
- it does not happen when steering is straight, so it's not gearbox related
- at higher speeds there is no humbling or other noises coming from the rear, so no typical differential issue noise

Recently my car had geometry aligned and change of diff oil at Lexus service. As it was winter, I didn't drive it much, but I'm pretty sure noise wasn't there before.

What I did:
- I put other wheels, but on another sets it makes the same thing
- I lifted car slightly, but couldn't spot any issue with diff or drive shafts - no leak, no damage

In the winter I drifted the car couple of times, but I'm almost sure the sound was not before last service.

Any clue what could I do before sending it to service? Can diff make such things?
Thanks in advance for any ideas.

jwgorrie

Hi what oil did they put in... if it's a 2008/9 it should be LT oil. If it's a 2010+ it should be LX oil.

Think the LX has some additives for 2010+ torsen differential.

Check your invoice.

Others will hopefully chime in with other ideas!

Piciu

Hi, thanks for pointing that out
I checked invoice and they did put LT...
I also noticed that this sound does not happen when cold. I will test today again to be sure that it only happens when hot.

Is there big difference between LT and LX? Manual says about LX, but can LT cause some strange noises in a diff?

jwgorrie

I had a similar issue after a service I noticed a noise when diff was warmed up after a drive and when turning any direction at slow speed. When in a straight line it was silent.

The oil used was the LT version not the LX. I challenged them on this and were adamant it isn't the oil causing the noise, so after a few days they said the diff was requiring replaced. I'm saying all this because I think I've been done! And if they just put the right oil in it first time It wouldn't have made the noise/vibration when turning at slow speeds once warmed up.

If you go back to the dealer and a change of oil to the LX type fixes your noise, I'll be interested and using this thread as evidence that my original diff wasn't broken, just that they put the wrong oil in it at the service initially. And I might get a refund!.

Whdn hen I got my new diff installed I noticed the invoice again had LT. not LX. So before I drove Away the service manager was informed, he took me to the lift, showed me tins of the LX oil and drained and filled. I wasn't chancing it, maybe I should have as it would have proven to them that the original diff just had the wrong oil??

since a year has elapsed I got my 60k service done, new oil again, this time the invoice does have the correct LX type listed, and no noise after a service this time, so keep us updated, as I may have a case against my initial issue, much appreciated

Piciu

When I contacted them, they said that for sure it's an error on invoice. But then I sent them copy of 'check protocol' and there was stamp of LT there. How do I know what is inside? So I requested full oil change for LX and they agreed to do it on Thursday.
I will report back if it changed diff's behavior. Hopefully it helps and then we will have a proof that LT <> LX for LSD cars.

BTW, how much is a new diff?

jwgorrie

I hope the oil change works, it cost me GBP 2k that's after lexus goodwilling a big % as I was out of warranty. So not sure of real cost.

I hope the the oil change works!

Please post back with results. Fingers crossed.

Piciu

Finally I had diff oil changed. They tried to convince me that LT and LX are the same, only Colour is different. And that the most important is to put always the same. With this I was told that 2 years ago I also got LT (yellow). But I insisted and they did put LX (red).
I was literally standing next to mechanic, so I saw yellow being flushed and red being pumped in.
On Friday I did usual drive and no strange noise at all. Today I did like 500km journey (so it was well warmed up) and still quiet. Nothing else changed about the car so for me oil change for LX worked well. Let's see how long it will be ok.

Hope this answer will be useful to some other guys too.

I will report back in a week after I return (another 600km)

jwgorrie

Good news so far!

Look ok forward to hearing your feedback over the next week .

j3ff

This thread is both interesting and helpful for the community. Thanks for sharing! Surprised your dealer believes it's just a colour difference. A quick Google search shows the LX has additives specific for limited slips.

Piciu

I'm happy to report that after 1300 km done after diff oil was changed to LX all is still silent. So definitely LX solved the issue.

jwgorrie

super news, glad to have helped...

I just wished I'd have pushed harder to try the oil change instead of them insisting the oils are the same / same code in system.

oh well! Lessons learnt 😞

Piciu

My dealer was trying to convince me the same - Service manager told me that they contacted suppliers and they were assured that these 2 oils have the same specification.
But I insisted and it paid off.

Thanks again for pointing out that there are 2 oil types, I would never find it out so quickly. This shows the power of user forums