Originally Posted by DaveGS4

This Friday I had my new Precision Industries (PI) Dragon Torque Converter (TC) with lower stall speed than my prior PI TC (2600 new vs 2800 old) and something called a 'turbo stator pump' that Mo at SRT suggested I ask that PI put in the build of my TC. I got a great deal on the new TC from our ClubLexus vendor JPI who hosted a group buy for five of these torque converters (thanks JPI!) which really pushed me to try this as a possible solution. That group buy is now completed & closed sorry.

Thanks to this thread I also hunted down a local Amsoil dealer and picked up a case of Amsoil synthetic ATF. I bought a case of it for $7 per quart, but only used six quarts for this go-round.

Oh, one other change that impacts info in this thread. I also have new 19" wheels on to update my configuration posted earlier, but I still had the same exact issue as I did with my 18s before doing the PI TC 2600 stall install. 19 x 8.5 front and 19 x 10 rear, 35 offset front, 42 offset rear. Tires are Pirelli PZero Nero 275/30-19 & 245/35-19

I had the PI TC install done at my local Lexus dealer, Hendrick Lexus. Think the install charge was something like $600.

Before the PMs start coming in, I have a potential local buyer for my TC already . If that doesn't work, I'll post it on CL.

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The Results:

I'll cut to the chase and say that the shift problem is 90% resolved for me ! There was fairly heavy traffic when I drove home from the dealership, so I didn't get a chance to really get into it. I got two decent accelerations in and it shifted fine for both of them, so I became optimistic. I drove it once last night and got into it a bit with no problems too. TomTNC came over today and he and I went out for a spin where I mashed on it several times on my back road proving grounds and it shifted like a champ. Only once did I detect any hint of revlimiter or hesitation in shifting.

Since I had both the synthetic ATF done and the lower stall TC done at the same time, I can't say for sure which was the cure. The fluid would seem to be an obvious and lower cost first step for somebody that already has a 2800 stall TC. If I were a betting man, I'd wager that it was the mechanical change that primarily fixed it and not the fluid.

The only *bad* think I noticed is that my car shifts more like it did when it was stock. I actually thought the 2800 stall PI TC improved the driveability of the GS and made shifting points both more natural, more agressive and with less hunting. The 2600 stall has taken some of that away. Not bad, just not what I've become accustomed to in the three + years since I had the 2800 stall converter put in.

The old TC also was (I believe) the cause for my check engine light to pop on. It never caused any issues with the car driveability, performance, etc just slightly annoying. I covered the light with black electrical tape and never thought about it. Since installing the new TC the CEL hasn't popped on.

Will post again if I see any additional hint of rev limiter problems as I get more miles on it.