Better fuel economy...that must be on the "test" bench fuel economy, because in the car my economy was at least 10% better with the 5w30. This theory is thicker oil, better compression, more power with less fuel equals better economy when pushing around 4000 lbs.

Now about the trans: My fluid was dark on the first drain and near bright red on the third. I will "drain refill" once a year just as I service my Hondas. Further, old oil is in there and you wonder why the thing shifts funny? How does this sound, "My car shifts weird, better start checking engine components"? Sometimes the solution is easy.

 

The opposite was true for me. Switching to the lighter oil solved my hesitation.

 

I pretty much do the same thing with my Hondas...just dump and fill once a year...have 285k miles on one of them, must be doing something right. The other one has 81k.

I attempted to do the same thing with my LS, but when I did the initial drain it was so dark that I decided I had better drop the pan - everything was fine, but at that point I did the filter and gasket. I've put 35k miles on it since so it's time to do a dump and fill, probably do it in the fall. And I've put 40k on my coolant since the last time I changed it, probably do that in the fall too.

How long have you been running the 5w30? Are you using synthetic? I wouldn't be opposed to giving it a try.

 

What you have had work for you is amazing...to do the engine clean and go to TGMO - and have it solve all your problems - is awesome. I wonder if your oil rings were gummed up or something and between the cleaner and the high quality synthetic, it freed them up/cleaned them.

 

I changed that trans fluid a couple times within a month; which is not an easy task (i.e. Hondas). The 2nd drain refill gave me back better looking fluid.

Royal Purple 5w30 will stay in there. 5w20 will spin free-er. In most driving conditions the engine should make enough torque so you don't have to work the trans hard with ye' ole' downshift request,

 

I only trust oil analysis. With oil analysis I don't buy the best oil money can buy but the best oil for the money.
RP has been shown to be not that much better then any other synthetic oil. Their transmission fluid is garbage and is very well known to eat brass and ruin transmissions. You are pretty much paying for the marketing and the purple dye to make their oil attractive so you believe in it.
Toyota oil is good stuff because the base oil is high quality and it's jacked up on Moly which is great for boundary lubrication.
If twenty weight oil is too thin for the rings then my car should consume oil which it hasn't.

 

Royal Purple's diff fluid is even worse. Too bad their products aren't nearly as good as their marketing.

 

That's because RP is a religion. RP got the beat down pretty badly for their claims and they have always been suspect. It doesn't matter what product you buy but if the color is not the natural result of a byproduct look out.

 

Open your car door, start your engine and listen to it come alive. You should only hear the belts. Chemistry and testing has limitations. You can hear unnecessary wear from insufficient lubes. (5w20 vs 5w30)

Ps:I have become an RP spokesman

 

I'm not saying anecdotal evidence does not have merit but you cant wish away data that suggests otherwise. Testing does have limitations but it gives us far more information then our five senses and that sixth sense that is routed in marketing.
Using thicker oil in a tight tolerance engine creates fluid friction. It may cushion moving parts and quiet it down but it doesn't mean it is preventing wear of the engine. What is most important is boundary protection that only additives can provide which is what Toyota oil has.
You also want an oil that has a very high viscosity index where thicker the oil the less VI is achieved.
I'm not against running higher viscosity oils but it is only warranted in matching the right viscosity within the proper heat range.

My car runs the Toyota oil and there are no unusual sounds windows up or down. If you have a loud engine there might be more going on that the thicker oil is masking.

 

In the last 12000 miles I tried:
Castrol 5w20, Mobil1 0w20, RP 5w30

Is Toyota oil produced by Mobil?
My data says at 65mph I'm getting more than 300 miles on 1/2tank of petrol. The Trans is flushed (refill method) and my kickdown delay has vanished. This is a friendly suggestion before swapping heads and trannys.

 

Toyota oil is made my Mobil to Toyota specifications and is not Mobil 1. It's not even PAO based synthetic like Mobil 1.
It's the additives that have everything to do with keeping wear numbers very low. We cannot go off generalizations and if there was a problem with running this specific oil it would affect millions of cars.

I'm in somewhat agreement that some 20wt oils may not be up to the task and 30wt oils might be warranted in many other applications but Toyota oil has address this with making from what we see in the formulation a clearly superior oil that so far has shown some of the best wear numbers I have seen from any car.

If you truly believe in RP I suggest getting a used oil analysis so we can compare numbers.
As far as transmission fluid goes we don't have one example of anyone that suffered any ill effects of not frequently changing their fluid and the car has been in service for almost 10 years.
You must first show an epidemic of failed transmissions due to fluid to warrant frequent replacement of fluid of solving any issue otherwise it's simply a case of absence of evidence.

 

With 40k miles, trans fluid is no longer red. Opposite of accounting: Red is good black is bad. Btw-this thread is about poor shift performance (ie fail). Before I purchased an LS I saw one struggle to pass on the road. #ezfix

O.E. post: "...at around 40 mph I floored it to pass and the engine revved like it was in neutral for 3 or 4 seconds (seemed like forever) before the transmission engaged and downshifted, then caught up with the engine rpms, and finally started to accelerate. No other car I've ever driven has taken so long to downshift and accelerate, and I was worried that I might not be able to pass in time. This was unexpected and is a safety hazard. Apparently this is not an uncommon occurrence, as Lexus issued Technical Service Bulletin L-SB-0033-08 in June, 2008 to remedy this problem."

 

I'm also wondering if I should go with a thicker oil. I have lifter noise upon start up that will last a good 10 - 15 seconds. Even when warm, if I start it after only sitting 30 min. I still get lifter noise for a couple of seconds ???? BTW, I still have some hesitation, I've put on 2400 miles on the oil change.

 

Have you tried my trick of keeping the rev's up above 1500 when cruising?