AZGS400

Does anyone make a shift kit fo the GS? It seems the way Lexus has the transmission programmed it slips a lot or hesitates between shifts. Part throttle is the worst . It's to the point you can't feel it shift. I am sure they didn't that on purpose for the old gummers who buy the car. I wish they would have a switch for shift modes like they do for power.

The shift kits for domestic are pretty reasonble price.

DaveGS4

iTrader: (2)

Haven't heard specifically of a shift kit personally, but several shops do a "valve body upgrade" that accomplishes much the same thing.

Examples:

http://www.swiftracing.com/engine/tranny.htm
http://www.rodmillenstore.com/gs_400...drivetrain.htm
http://www.rodmillenstore.com/is_300/valve.htm (link says IS, but it is from GS menu)


IMO high stall torque converter helps too, but doesn't specifically address the tranny issue like the valve body upgrade.

FutureGS400

Take a look at this:
http://www.levelten.com/hydrosystem_import.htm


Shift kit and valve body upgrade =same thing.
BTW, the power mode switch does affect the shifting points (not the actual shift itself which is what you want). It does not have any affect on the actual power of the car.

SeattleGS400

iTrader: (1)

AZGS400:

Sounds like the obvious, but have you checked the condition of your ATF? If it's a bit older, brown, or black, it'll affect how your car shifts. New ATF will get your transmission shifting better (assuming that your transmission is in good working order). Also, as FutureGS400 mentioned, use the POWER switch for a faster and higher shift point. The POWER switch also has better throttle response, so it doesn't seem like the car is slow to react all of the time.

jmecbr900

I don't think the power switch will cure what he's referring to. I believe he wants firmer and quicker shifts. That can only be achieved via VB mod or tranny ECU recalibration/reprogramming.

Personally, I have a VB mod in another car. It is extremely harsh for everyday driving. I'm sure there can be different levels of aggresiveness that can be done by the mechanic, but it definetly changes your ride quality.

Some people here have the SRT tranny upgrade or RMM tranny upgrade. I've been told by one of those people that the ride was not harsh at all. I believe he got both the VB and the ECU redone, so he maybe found the jackpot.

I would love to find someone that can take my ECU and reprogram it to keep from cracking open the tranny again. Toyota ATF is as expensive as liquid gold.

fireballs gs400

any you guys who have the valve body upgrade, whats the weight of the spring that was installed? curious b/c a tranny guy said he could replace the fac springs with heavier springs, which would make the shifts more firm. anyone?? thanks

HI98GS

I have the valve body upgrade. You don't change the springs. The upgrade did not come with new springs. I believe that the channels may have been widened somewhere so that the flow of the fluid would be better. I tried to compare the stock and the ugraded one, but from what I could see the modification is internal. All the solenoids are stock. The car shifts very well and I am exteremely pleased with the overall performance.

fireballs gs400

i don't know if i should have him check it out...could mention it...so what would happen if heavier springs were replaced? any idea. i recall you bought your valve body used from someone....what are some of the differences?

HI98GS

My valve body is brand new. I did buy it from "itsallgood" but it was never installed in his car. The valve body was originally purchased from SRT.

jmecbr900

How does it shift? Is it harsh?

As I said, the only VB mod I am familiar with is very harsh (race car like. Squealing the tires everytime in the 1-2 shift).

I would be very interested in this if I knew that it would not make my car harsh. I can take positive shifts and even extra firm @ WOT. Just don't want the "banging" gears feeling.

Any help would be appreciated.

RMMGS4

iTrader: (5)

I have the RMM valvebody and the tranny shifts are crisp and smooth, with no delay or slipping, even at partial throttle. I can feel the tranny when it shifts gears, but no "race car like" hard shifts tho.

To put it simple, I have not experienced any of the problem conditions that AZGS400 described in his original post.



.

jmecbr900

Would you honestly recommend it to anyone else (me)?

Do you have that barking tires shift between 1-2 or is it more positive shifting and smooth?

RMMGS4

iTrader: (5)

No barking , just positive, clean shifting. Not hard at all, just a nice crisp shift.

Recommendations ? Well I have no complaints. If Steve can get it for you cheaper than RMM direct , I'd say go for it. I think the SRT valvebody mod appears to be one you should consider too.

jmecbr900

Thank you for the info.

TTurboPimp

iTrader: (12)

I just recently had my SRT VB upgrade, upgraded again by SRT. Apparently they have a new and improved version of their VB upgrade, and it definitley is just that. I would highly recommend SRT's VB upgrade to everyone....its well worth it.