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

 

This particular trans issue I've not read about before. So this one is new to me. But like the specialist said, he was spot on about it coming back. To be honest, I'd not spend money of a rebuild (especially for $3k), when you can source a good, used trans. I fear that, depending on how deep the rebuild truly goes, that your problem arise once again after being rebuilt. My brother spent $3,500 on his Acura TL trans to be rebuilt with OEM parts. After just 13 months (1 month after the 12 month warranty was up) his trans went out AGAIN in the same manner as previous. He now has a useless car that just sits in his driveway. The "5 start" import repair shop that did his trans won't help him out at...not a penny! BOO YOU First Class H.A.L.T.!

 

I totally agree with the above. With several people I know, transmission rebuilds always come back to haunt you, the problem usually comes back. Just like above, my brother-in-law rebuilt his Honda Odyssey's transmission two different times at $1800 a piece, and the same issue would arise after 6 months. After the third failure he gave up and gave the car away to a family member and bought a new Odyssey, that family member instead of finding a good used one had it rebuilt for a third time, and ended up junking it after it failed again

 

I don't recall if my 350 goes into TCC lock up at 30mph cold but I think not. That said, if your engine temp is reporting the engine as warmer than it should be, it could allow the trans to jump to lockup while the engine is in fact cold.

Strongly advice the purchase of OBD Fusion and the Toyota Lexus Scion add on PID pack.

Now load the engine and trans temp as well as everything shown below. As I know it, the trans should not go into lockup while the engine is cold like below 170°F...
Notice the lockup status on this screen shot.
Look and see if your trans is in TCC lockup. If yes, depress the brake pedal just enough to trigger brake lights but not slow the vehicle.
Does the shutter stop? Note; depressing the brake is supposed to take trans out of lockup to prevent stalling the engine.

 

Thanks for that story man, got me quite scared now. This transmission specialist gives a 24k miles / 24 months warranty with their work so I guess that's something...but I just don't want the headache of it breaking again within my ownership...!

 

Thanks for giving your story man, that really sucks, I'll tread carefully.

Thanks a lot for that info man, very helpful, I actually have also been thinking if it's all because the engine is willing to start using lower revs (as it gets warmer) but the transmission isn't ready for it yet. Then when both are at full temp, they are happy to work together again.

Really appreciate your input, will look into all of this.