bmgs400

I've been studying posts on TCs carefully and I like what I've read. But, I have recently been into the Lexus dealer to get a starter replaced and talked to a mechanic about the TC upgrade I'd like to do...trying to get a cost estimate for the TC swap. He mention one he did on an SC, said it was 2400 stall speed, and said it "hurt" it's "drivability" around town. He also said it won't improve shifting..."it's controled by computer" and doesn't recommend a 2800 stall speed TC at all.

I also asked about cost to replace the rear diff with a bolt on LSD replacement diff.

In the end he suggested getting a used GS300 (3.92) diff and doing a valve body upgrade. Says the valve body upgrade will be cheaper to install and will improve shifting if the kit has all the right parts.

I'd like to do a TC upgrade, but now I wondering if it will degrade it's drivability. Should I take his advice and just do a valve body upgrade instead?

DaveGS4

iTrader: (2)

IMO he's incorrect.

The valve body upgrade (at least mine does) makes shift MUCH harder and faster, which definitely reduces the luxury feel of the car. There are minute jerks as it goes into gear at times, especially when the car is cold (more apparant). I would not have done this upgrade unless I got forced induction.

The 2800 stall works great with the GS and my observations improved overall driveability, reduced the car 'hunting' for gears as much. Many other members have the same observation - just search to read what they have to say.

If your mechanic didn't mention the potential for serious traction issues with doing a 3.92 gear with an open differential (spinning one wheel) in your GS, IMO stop taking his advise.

I'd advise you find somebody local (go to a FL meet) with the TC and drive/ride in one to make up your mind on the driveability.

bmgs400

Thanks DaveGS4! You've helped my confidence level. Maybe there's some unique differences between the SC and the GS4 models?? He's never test a GS4 with the TC mod and doen't know of any with a mod. I was hoping to find an experienced mechanic in this area.

You're obviously correct about the traction concerns with 3.92, but maybe he's assuming I'll keep VSC on all the time. I'm still leaning towards the 3.76 LSD.

I was wanting to attend the Orlando showing, but couldn't make it. I'd very much like to check out GS4 with the TC upgrade. Any one in the Tampa/St.Pete area got one?

rominl

iTrader: (4)

i have to agree with dave. i have the gs4 with tc and i do more local driving than freeway, and the drivability of the car is awesome with the 2800 stall speed. no change at all. it's all good, go for it

bmgs400

I've checked out the website for Precision Industries. I didn't see a TC for 98~2000 GS4 and what they did list specs a 2400 stall speed. Is their specs wrong and/or available parts listing incomplete?

Whats CL members choice...PI Dragon TC or RMM TC? Whose a reputable distributor?
About how much should my Lexus dealer charge me for this installation? I expect at least 8 quarts of Toyota tranny fluid will be needed...but labor cost and other "incidentals"???

bmgs400

I've checked out the website for Precision Industries. I didn't see a TC for 98~2000 GS4 and what they did list specs a 2400 stall speed. Is their specs wrong and/or available parts listing incomplete?

Whats CL members choice...PI Dragon TC or RMM TC? Whose a reputable distributor?
About how much should my Lexus dealer charge me for this installation? I expect at least 8 quarts of Toyota tranny fluid will be needed...but labor cost and other "incidentals"???

DaveGS4

iTrader: (2)

They are right here and list a range from 2400 - 6000 stall

http://www.converter.com/dragon.htm

Order from somewhere other than the vendor that knows specifically what to ask for - I know Steve Ganz carried them and I think TM Engineering did as well. JPI's group buy was a one-time deal.

I'm pretty sure the RMM TC is simply a rebadged Precision Industries TC, although they might use Level 10. They don't make their own.

rominl

iTrader: (4)

from what i know the rmm one is PI too. but yeah, i would just get it from carson or tm engineering

bmgs400

I see...thanks. I just noted the bottom end RPM of the spec's...my bad. So a 2800 RPM is better over a 2400 as many CL members have experince...good to know.

How much would this cost to install?

rominl

iTrader: (4)

yeah those of us with NA gs4, i think most of us hae the 2800 stall speed, awesome stuff i have to say.

install? i say around 600 bucks the least, including fluid

daleer

$600 ?? Crap - do you think that it would be cheaper if I'm getting my suspension done at the same time?

TLW

IM GOING TO SAY NO

maybe if you were doing a VB upgrade or something else with the trans

but its been my understanding that they only give breaks when they are already working on that part

but if im wrong let me know

rominl

iTrader: (4)

they have nothing to do with each other.... when i did my tc mechanic didn't even have to take off the wheel