$700 to replace spark plug

No, it will not harm your transmission when done correctly and or on time as long as the manufacture (Lexus) doesn’t say other wise… Flushing a transmission will get almost all the ATF exchanged, including the torque converter and moat all the clutch packs etc etc normally… If Lexus says it is OK to flush, then flush it, check your owners manual to see if/what it says… We are not talking about if the dealer says it’s time to service the transmission or not, only that it is OK to flush or not…

What people are scared and talking about damaging the transmission is when it has never been serviced and then you want to service it at high milage and or you start having trans issues…

I wrote this a while back and it is about automatic transmissions in general…

Changing your fluid cannot cause any damage by itself, if everything is fine inside the transmission… The issues start to appear when you change the fluid if your clutches are already worn or damaged from use. If you go and replace the fluid after they are already worn out. this can cause slipping…

For more info and pictures, click on link and read away…

Transmission Flush vs Fluid Change: Which is Better? : AMSOIL.

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Plus, you probably paid your bills net 30. That is also very attractive to the supply house because although the bigger shops order more parts, they probably have negotiated net 60 or even longer terms.

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Yes, and I even did any and all returns ASAP so it would not effect the next months sales for the parts places, or my GP… I was very OCD about the bills being paid…

Curious, was this due to concerns regarding quality?

Back when it was the worst, everyone was doing whatever it took to keep the pipeline moving. Substituting materials with minimal qualification, ordering parts from brokers and the grey market etc. I know one place was harvesting hard to find parts off sample boards and older equipment to make deliveries. We even had issues with adhesives where they were substituting in different raw materials that significantly altered the performance of the product. It took a lot of leverage to get them to admit they had made a change. Unfortunately, based on what I experienced, even the legacy, reliable suppliers were doing questionable things so the dealer suppliers probably weren’t protected either…

This topic will be hotly debated here again. All I can say is I just have the fluid changed every 30,000 miles without fail and never had a flush done myself. My first service was at 10,000 then every 30 after that. Neither the dealer or trans shop has recommended a flush, so I just play it safe.

Yes, that was what he said.

Thanks everyone.

When it comes to the user manual I’m very weary of reading it for one reason. There are tons of things to read. The book is very thick and when I skip through to the maintenance page very little information is found. It usually suggests me to consult my warranty guide book for more info, then I have to go through a ton of pages again. It’s a very complicated manual which is why I haven’t bothered with it.

This forum has been extremely helpful though and it provides knowledge and peace of mind from you guys.

Many thanks. :v:


Information in the owners manual is sketchy at best. More detail is in the factory repair manual which most owners don’t buy.

On one car when we got to the end they agreed to throw in the service manual in the deal. It was one out of the shop from the year before with the current year update. Still had all th3 information and saved m3 $200. Just like buying a used book. Still good.

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The merits/demerits vary car to car, but here’s one shop-owner’s view of the trans flush procedure.

A little more information on draining vs. flushing the ATF:

My 2005 Honda Accord with the V6 and automatic transmission could not withstand a flush according to the factory. Their preferred method was to drain and drive three times before calling the job completed. Up to one third of the fluid remained after draining and driving the car mixed the ATF so that in the ensuing two drain cycles there was very little of the original fluid left. If you drain rather than flush you might need to do the drain/drive cycle described above. That’s another good reason to go with the flush.

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The shops i managed would not install customer supplied parts.


If possible (a lot of newer transmissions can’t be) do a flush and a pan drop with new filter…
I guess it is better to call it an exchange than a flush, but not trying to split hairs here…

When I was doing transmission daily, we offered either or, or both… A pan drop doesn’t get all the fluid out including the torque converter or the cooler, but a flush/exchange doesn’t replace the filter either…
Now, a lot of trans these days don’t have a pan to drop much less a serviceable filter, and some trans have an external spin on filter and no pan and some a mix of those…

I refer to that as “drain and refill”

I’ve heard other guys call that “spill and fill”


Ha, I thought I was the only who had that thought. How could we prove the plugs were replaced, right?

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The first time I did plugs in tranverse V6 was an old Caravan ('85?) . Up until then I’d done small engines, 4cyl or 6cyl longitudinal mounts (straight or V, doesn’t matter if it longitudinal). No biggie.

Then I looked at what it took to do those rear/left/bank 1 plugs in the Caravan and thought AYFKM! It needed to put it on ramps to get, I think, the #1 plug from underneath and even then with some manner of combination of u-joints and extensions. Holy sh…oot. One of the many times I said “I need a lift.” And a good chiropractor for when I’m done. Insanity.

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Actually, when I was still working at the dealership, a guy DID get in trouble for not actually installing the parts he was paid to install

This guy had long been under suspicion

So one day, while he was at lunch, his locker was opened . . . it was full of several thousands of dollars of new parts, still in the packaging

He had no plausible explanation for this


Yeah I went with dad about 5-6 years ago when he dropped his Infinity I35 off at an indy shop, I asked them to please install OEM spark plugs vs Bosch or some other plug… I was really hoping that they didn’t charge for and skip the 3 rear plugs… Well fast forward when the CEL kicked out a P0303 code (rear plug) I really was wondering, but when I had my son pull all the plugs they were all correctly done…

The reason the thief I mentioned was under suspicion was that he was flagging so many hours that it wouldn’t have been humanly possible to be that efficient

And he was openly and loudly bragging about all the hours he was flagging, that he was faster and better than all the other guys

The other guys were experienced, fast and efficient and here was this loudmouth who seemed to be doing very little, yet he was flagging all these hours :face_with_raised_eyebrow:


I have known a few of those…

I see this mentioned on the tv show “America’s Truck Night” . They have their own shop with lifts so the competitors can make repairs, tuneups, etc. They check the condition of the hard to reach spark plugs first , b/c those plugs are frequently never replaced.

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