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Quick response needed

Old Oct 27, 2025 | 07:00 AM
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Shop is presently working on ABS issue and asked about spark plugs. Apparently plugs are due at 120K and its at 128K miles.. I did authorize the transmission drain and refill.

I'm unfamiliar with the necessity or urgency for plugs to be done and what reasonable cost might be (they quoted ~$1600 for parts and (mostly) labor.)

Any feedback and expertise would be appreciated.

Last edited by Finalist0946; Oct 27, 2025 at 07:11 AM.
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Old Oct 27, 2025 | 07:06 AM
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Originally Posted by Finalist0946
Shop working on ABS, just asked about spark plugs and transmission (I assume drain and fill but they did not share specifics yet). Spark plugs are due at 120 I think, no service has been done on transmission since we bought it used at 80K miles.

Any thoughts - need to let them know in next hour

Drain and Fill only using ATF-WS
Spark plugs. OEM due 125k can be pushed longer but yes
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Old Oct 27, 2025 | 07:11 AM
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The auto shop I'm taking the wife's RX said it will do a transmission fluid analysis. Results will determine whether to do a complete fluid change or small drain and fill. I'm not a mechanic but that made more sense to me than an arbitrary decision. Currently at 108k miles. Toyota did a transmission "flush" on myTundra at 100k and 200k miles. At 300k miles transmission still operates like new. Good luck.
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Old Oct 27, 2025 | 07:12 AM
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pushed how long (don't worry I won't hold you accountable - just want to get a sense)
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Old Oct 27, 2025 | 07:15 AM
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Originally Posted by Finalist0946
Shop is presently working on ABS issue and asked about spark plugs. Apparently plugs are due at 120K and its at 128K miles.. I did authorize the transmission drain and refill.

I'm unfamiliar with the necessity or urgency for plugs to be done and what reasonable cost might be (they quoted ~$1600 for parts and (mostly) labor.)

Any feedback and expertise would be appreciated.
Please consult the Service and Warranty booklet and at least bring service up to date.
My suggestion is to stick to OEM parts [spark plugs etc]
History of service at Lexus can be pulled from Lexus site or from the dealer.

Salim
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Old Oct 27, 2025 | 07:33 AM
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Originally Posted by Finalist0946
pushed how long (don't worry I won't hold you accountable - just want to get a sense)
until you get a misfire
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Old Oct 27, 2025 | 07:36 AM
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OK, so two follow ups:

What would a misfire sound like, and
Once that happens, is any damage done or are we still OK but need to get it done then? Would the car still be driveable to get it to the shop??
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Old Oct 27, 2025 | 07:38 AM
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I think you should just get it done haha. You also make sure that they do Temp Level check when they do drain and fill. Most shops I know won't wait for transmission fluid to cool down before doing transmission levels. But YMMV
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Old Oct 27, 2025 | 07:47 AM
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You typically do not hear a misfire. It shows up as an OBDII code P03XX (with XX being the particular cylinder in which the misfire occurred, so a code P0302 indicates cylinder number 2).

Denso and NGK iridium spark plugs can easily do 150,000 to 200,000 miles or more.

I would use only Toyota WS ATF or Idemitsu ATF Type TLS-LV.
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Old Oct 27, 2025 | 07:54 AM
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I am getting trans done. Fluid was not hot when they did the flush. They are using ATF-WS fluid

Last edited by Finalist0946; Oct 27, 2025 at 07:55 AM.
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Old Oct 27, 2025 | 07:57 AM
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Originally Posted by Finalist0946
I am getting trans done. Fluid was not hot when they did the flush. They are using ATF-WS fluid
I would not "Flush" but instead Drain and Fill with that high miles...
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Old Oct 27, 2025 | 07:59 AM
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I know its been discussed here ad nauseum, but give me your bullet point reasons (rationale) for a drain vs flush
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Old Oct 27, 2025 | 08:03 AM
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Flushing ATF can drag long-settled debris up from the bottom of the pan and through the valve bodies, causing operational issues that were not there before. I never flush, I only drain-and-fill.
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Old Oct 27, 2025 | 08:20 AM
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The quick of it.

A transmission flush can cause issues on older high mileage transmission with possible debris making it way to the valve body as you seem to notice being discussed on every forum by every automaker so as this one and therefore pose an greater risk than a drain and fill service. You read the information so decide which route to take based on the available opinions on it.

As for spark plugs my 2015 Rx350 still had the original plugs at 190k miles before I changed them and the engine still operated, but was down on power and had very poor fuel economy as the plug electrodes were very worn. I would assume that eventually my engine would have started to misfire when the plugs finally were unusable due to too much wear.

The OEM plugs should be changed by 120k miles for "proper" engine operation.

Last edited by carguy75; Oct 27, 2025 at 10:58 PM.
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Old Oct 27, 2025 | 09:13 AM
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Originally Posted by RX in NC
Flushing ATF can drag long-settled debris up from the bottom of the pan and through the valve bodies, causing operational issues that were not there before. I never flush, I only drain-and-fill.
Never thought of it this way. Huh! I guess that is why so many guys think a flush can cause problems. I always thought of a flush as dropping the pan, getting all the goop out, changing the filter, putting it back together and then actually performing the flush.

BTW - $ 1600 sounds steep if that is just for the plugs. IDK.

Last edited by SunglassesGuy; Oct 27, 2025 at 09:15 AM.
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