Transmission judder issue

azriz · February 24, 2020

Hi guys,

I’ve got a 2008 IS250 automatic on 92k miles that started developing a judder between 30-36 MPH when the transmission shifts in to 5th gear (low RPM at that speed) and the drivetrain temperature is above cold, but not yet at full operating temperature. It feels like you’re driving over a rumble strip of some sort, and it feels like it will happen infinitely unless I let off the throttle and re-apply, or kick it down so it drops a gear and brings the revs back up.

Once at full operating temperature, the issue goes away. When you let go of the throttle, the juddering instantly stops, and if you push deeper into the throttle it downshifts a gear and stops the juddering.

Once the car is at full temp, there are no issues, it drives like a dream.

I can quite consistently make it happen (not that I want to!) by doing this:

- Start car from cold
- After about 10 mins of driving, slowly accelerate up towards 30mph
- Once it shifts into 5th at 30mph, continuing the same light throttle input will cause it to happen
- I have to let off the throttle and re-apply it to stop it happening, and then I get a tiny bit more aggressive on it so it keeps the revs up above the 1400ish mark

Its required conditions seem to mainly be:
- 30-36mph
- Just shifts into 5th gear, so revs are low at around 1100 rpm
- Light throttle, gentle acceleration
- drivetrain still below full temp, but well above cold
- it’s extra easy to replicate the issue when you’ve driven the car to full temp, park up and let it sit for 45-60 mins to start dropping temp a bit, set off again, and when you meet the above conditions, the judder is super obvious

2 months ago I had the fluid and filter replaced at a transmission specialist. They also added an anti-judder product in hope of fixing the issue.

They noted that the fluid came out very dark, much worse than they would expect at 92k miles. The tech that spoke to me said that he fears it will fail not too long from then.

The car drove great after the service, the juddering went away for a few weeks.

However it has unfortunately slowly returned and has now reached the original sort of level of problem. It’s been about 1k miles since the service.

Has anyone experienced this sort of issue before? I’ve been desperately trying to research this issue over the last 4 months and what I’ve found is that there have been some cases of the torque converter failing, mainly in the USA I think, and replacing the TC fixed the issue.

I don’t want to chase a transmission problem and find out it’s actually somehow misfiring in the engine due to carbon buildup or something! (I’ve read codes on a phone app and none are stored, and the CEL has never come on in this car - I think it usually flashes during misfiring on most cars right?).

I’m thinking to give the car in to the transmission specialist to have the torque converter rebuild, and all fitted back up with fresh fluid etc. This will cost me about £1k.

If the issue is even worse, I’ll be looking at nearly £3k for a full rebuild of the whole box, but with the car being worth like £3.5k I’m not sure it’s worth doing…

One of the cases I found seems to mention the same issue here: https://www.justanswer.com/lexus/9gp5g-intermittent-problem-car-low-speed.html

Thanks in advance for any insight or advice.

Regards
Az

Alfalfa · February 24, 2020

1 hour ago, azriz said:

Hi guys,

I’ve got a 2008 IS250 automatic on 92k miles that started developing a judder between 30-36 MPH when the transmission shifts in to 5th gear (low RPM at that speed) and the drivetrain temperature is above cold, but not yet at full operating temperature. It feels like you’re driving over a rumble strip of some sort, and it feels like it will happen infinitely unless I let off the throttle and re-apply, or kick it down so it drops a gear and brings the revs back up.

Once at full operating temperature, the issue goes away. When you let go of the throttle, the juddering instantly stops, and if you push deeper into the throttle it downshifts a gear and stops the juddering.

Once the car is at full temp, there are no issues, it drives like a dream.

I can quite consistently make it happen (not that I want to!) by doing this:

- Start car from cold
- After about 10 mins of driving, slowly accelerate up towards 30mph
- Once it shifts into 5th at 30mph, continuing the same light throttle input will cause it to happen
- I have to let off the throttle and re-apply it to stop it happening, and then I get a tiny bit more aggressive on it so it keeps the revs up above the 1400ish mark

Its required conditions seem to mainly be:
- 30-36mph
- Just shifts into 5th gear, so revs are low at around 1100 rpm
- Light throttle, gentle acceleration
- drivetrain still below full temp, but well above cold
- it’s extra easy to replicate the issue when you’ve driven the car to full temp, park up and let it sit for 45-60 mins to start dropping temp a bit, set off again, and when you meet the above conditions, the judder is super obvious

2 months ago I had the fluid and filter replaced at a transmission specialist. They also added an anti-judder product in hope of fixing the issue.

They noted that the fluid came out very dark, much worse than they would expect at 92k miles. The tech that spoke to me said that he fears it will fail not too long from then.

The car drove great after the service, the juddering went away for a few weeks.

However it has unfortunately slowly returned and has now reached the original sort of level of problem. It’s been about 1k miles since the service.

Has anyone experienced this sort of issue before? I’ve been desperately trying to research this issue over the last 4 months and what I’ve found is that there have been some cases of the torque converter failing, mainly in the USA I think, and replacing the TC fixed the issue.

I don’t want to chase a transmission problem and find out it’s actually somehow misfiring in the engine due to carbon buildup or something! (I’ve read codes on a phone app and none are stored, and the CEL has never come on in this car - I think it usually flashes during misfiring on most cars right?).

I’m thinking to give the car in to the transmission specialist to have the torque converter rebuild, and all fitted back up with fresh fluid etc. This will cost me about £1k.

If the issue is even worse, I’ll be looking at nearly £3k for a full rebuild of the whole box, but with the car being worth like £3.5k I’m not sure it’s worth doing…

One of the cases I found seems to mention the same issue here: https://www.justanswer.com/lexus/9gp5g-intermittent-problem-car-low-speed.html

Thanks in advance for any insight or advice.

Regards
Az

How much fluid did you change?

azriz · February 24, 2020

34 minutes ago, Alfalfa said:

How much fluid did you change?

They dropped the whole pan apparently, and said at least 5L would be replaced.

Alfalfa · February 24, 2020

If they only drop the pan you only replace about 1 litre. I had something very similar with my car that happened in uphill driving in low speed, 1000-1200rpm. Not all the time. I did a flush without cleaning addesive (oil only) this problem is now solved, the gearbox is shifting gear much faster and the strange thing is that the engine is getting the normal temperature much faster. My car had 250000km on the meter when the flushing happened. I did the flushing because of the high miliage not the juddering, but the first thing i did after flushing was to try the hill in low rpm, and no problem. Please read the thread about changing gearbox oil.

azriz · February 24, 2020

4 minutes ago, Alfalfa said:

If they only drop the pan you only replace about 1 litre. I had something very similar with my car that happened in uphill driving in low speed, 1000-1200rpm. Not all the time. I did a flush without cleaning addesive (oil only) this problem is now solved, the gearbox is shifting gear much faster and the strange thing is that the engine is getting the normal temperature much faster. My car had 250000km on the meter when the flushing happened. I did the flushing because of the high miliage not the juddering, but the first thing i did after flushing was to try the hill in low rpm, and no problem. Please read the thread about changing gearbox oil.

Thanks for the info mate, the shop assured me that at least 5L of fluid would be replaced so I'll ask them about it again but I doubt they would have lied or anything. And it was Toyota WS fluid as required, I was sure to clarify that with them.

I've done pretty extensive reading on the whole topic (found a good few threads on this forum and ClubLexus that have spanned a good few years) but am still open to any ideas or info at all to save me having to spend £1k for the TC replacement or £3k for a full box rebuild.

Thinking to get the spark plugs replaced first JUST in case that helps at all, but I'm quite certain that this is a transmission issue and not engine related, unfortunately.

Will also do an ECU reset by disconnecting the Battery for 60 seconds, to see if the reset of the adaptations helps.

Alfalfa · February 24, 2020

The gearbox have 7.2 litre oil, i can only give you my story.

Alfalfa · February 24, 2020

Auto Transmission Fluid Change - Anyone Done It?

Alfalfa · February 24, 2020

I realy dont understand how they can replace 5L from the gearbox, you can change 7.2 litre bay flushing and about 1 litre bay drop the pan or open the drain plug, i would be close to call them liars in your case.

is200 Newbie · February 24, 2020

I would have to agree with Odd Alf (nice user name !) i have read on here that the box holds over 7 litres also. A change via dumping the oil by the pan would require a few continual changes before it was kind of replaced.

By the info you have been given by the garage i would tend to question how they have stretched 5 into over 7 litres. Its a tricky job to change the oil in these and all sorts of parameters need to be met before during and after the change - certain temperatures need to be met during changing it etc ... Could the box be overheating? The box shares the engine coolant, check the condition of that to see if its ok as an easy check.

Alfalfa · February 24, 2020

Some input in another thread from me.

azriz · February 25, 2020

@Alfalfa thanks for all your input mate. I see what you're saying. These guys are a proper transmission specialist with supposedly a good reputation, I'm quite sure they have equipment to pump fluid hence the 5ish litre claim. They are a ZF approved garage so I'm sure they have pretty good equipment. I might give them a call to discuss it though.

@is200 Newbie that's a good point, the technician said the old oil came out surprisingly dark and bad for this mileage, and he said that something seems to be burning it. Not sure what, though...

All food for thought as I chase this further.

Thanks again, any more input is always welcome.

Alfalfa · February 25, 2020

I dont know what you have asked them to do, have you asked them to flush and change filter, or change filter only? The difrence in oil use is about 6.2 litre.

in Norway the flush cost about 500£ and filter change about 350£ included filter casket and 1 litre oil. So my cost in Norway was about 800£. Probably cheaper in the UK.

I can also tell you that the when i asked the meckanik that was using the flush unit that i was going to change filter on my car, hi told me that Flushing was not neded, i told him that i dont care and want the flushing. Lexus Norway dont rekomend Flushing att all, they had never done it on a Is250.

is200 Newbie · February 25, 2020

Search for the thread Autobox oil change on this forum

I started to have my autobox oil changed back in 2017 but not long after the car was written off (accident) i started to post the process up but then stopped as i didn't have the car after the accident. I had the garage, which is no longer in business so cant ask them any advise for you, take a picture of the old v new oil - pictured below ... there was also a burnt smell from it as i can remember. I had the car for quite some years and was looked after - have a look at the post above as theres some good info on there ...

The bag of dark oil is the old stuff - the red one is new

Alfalfa · March 11, 2020

How did it work out?

azriz · March 18, 2020

Hey, sorry for the delay, didn't realise that I don't get email updates from this forum.

So I decided to sell the car off for a loss and buy a replacement instead, was tired of the hassle of minimal knowledge and lack of support for Lexus cars round my way.

Unfortunately I won't be able to write up a solution to this issue for anyone 😞

Thanks again for the help everyone.

July 29, 2020

Low on oil was the verdict on my change yesterday, somebody had done it maybe diy and not filled Up enough and to fill it you need 2 people mine was done at southern auto transmissions in Hailsham East Sussex 180 all in