I have an '01. The automatic shifting is so smooth it's hard to tell when it's happening (except slight drop on tach). Manual downshift (5>4>3) also ultra smooth. Car has 101k and I bought at 89k.

Just bought an '04 w/ the 6 speed. Doesn't seem to be as good. Best is moderate acceleration. Smooth shifts at 2,200. Slightly up/down notchy when in stop and go traffic. Manual upshift slower response (unless full power like 5k+). On manual downshifts, 6>5>4 works smoothly but 3>2>1 not smooth unless pretty much at the right rpms. I've had the TSB done. No difference. Also just had a drain and fill. Car has 102k. I've only driven 400 miles so far.

The '01 trans feels super smooth. So far the '04 doesn't seem quite as good. Fun to manual shift of course and slightly better MPG. Comments?

 

I did not drive the 5sp trans. But things to check.
1) Engine Mounts.
2) Transmition mount.
3) Drive shaft central Bering & the coupling at bothe ends.
4) Difrential bushings.
Any of one above will effect the drive train smoothness to a leval. Sometimes the part is not totally worn but the rubber is drying out and loses its elasticity.

Regards.

 

I currently have a 98gs400 and 98 ls400, i love both transmissions. The gs4 has the shifting on the steering wheel for manual mode which is nice. I prefer the 5 speed over the 6spd, the 6spd shifts to fast, and I prefer taller gears then short, oh and also the 5spd's get a dip stick so i can check the condition periodically and do the two quart tranny fluid change interval with every oil change, doing a drain and refil on these cars are actually much easier then an oil change, even easier when your doing both at the same time.

 

The 2004 models had a TSB for a transmission reflash, and many owners never got the service done. That could be the issue.


Mine had never gotten it, and it made a big difference when I did. Before, it had a "rubber band" feeling during stop and go traffic. It was even noticeable to people not driving the car. I'm amazed Lexus let the car be sold that way.

It's well worth having a dealership check and do the reflash if it hasn't been done. Do some searches on here and find the exact TSB and bring it in, my service advisor was largely clueless.

 

Thats interesting, you would think that the 6spd would be smoother than the 5 everywhere. Let us know where this goes.

 

drain & fill will replace about 3 quarts of the 11.5 quarts in the system. after 100 thousand miles that is probably not going to make much of a difference. I did 2 drain and fills about 1500 miles apart at 95,000 miles. smoothed out the rough shifting I was having on cold starts. the guy in Virginia had the TSB done at accost of $220 I believe. only you can decide what is best for your car. I would get another drain and fill, mine were about $175 each at the dealership in Lubbock. decided not to pursue the TSB thing as I am happy with it now.

 

Thanks for the feedback and suggests. I am going to do another drain and fill in 1,000 miles. I did the TSB. Cost was 105 at a local independent w/ certified Lexus mechanics. As far as I could tell, made no difference. Actually the car shifted better before the drain and fill. Maybe another will help.

 

Thanks for the feedback. Worn engine and transmission mounts sometimes noticeable at idle (slight roughness). The mounts on my '01 are wearing. Sometimes there's a very slight roughness at idle. Barely noticeable and sometimes not there at all.

 

This is good advice. I would also try disconnecting the neg battery post for 5 minutes and then reinstall. Sometimes this can reset and the tranny will relearn the driving shifts under your driving conditions. I would also make sure you have a clean fuel system...

 

I've had my 02 LS for about a month now and I've noticed on cold starts I can feel the car going to 2nd and 3rd gears but once it warms up I can't feel a thing. Looking to do a trans fluid swap soon.

 

I test drove a few 01-03 and what stood out the most to me was how much smoother the 5spd is compared to the 6spd in our 06. The 5spd is literally invisible. The 6spd might be faster or have better fuel economy but if I had a choice I'd rather have the 5spd in our 06.

I had a tranny drain and fill two months ago and it made things a little smoother for the 6spd but I can still feel every slight shift. I couldn't feel a thing from the 01-03 5spd even when I tried to pay attention to it -- it feels like a 1spd based on how smooth it was.

Agree with the earlier post that the 6spd shifts smoothest under moderate throttle and around 2200rpm. I may need another tranny flush and fill...or maybe five.

 

I notice the same issue from my 06 when shifting from 1-2-3. The only time it shifts smooth is when the outside temp is around 70 or lower. I've tried replacing temp sensor, MAF, transmission drain & fill, and a few visits to Lexus which couldn't reproduce the symptom. Resetting the battery works for about 100 miles until the ECU learns my driving behavior (which I don't drive erratic).

 

My 2004 LS 6 speed has been largely perfect on the shifting, I would not call it harsh, far smoother than other cars.

My point is, if you have a lot clunking or really firm shifts in everyday driving, I think something is wrong and its not the 6 speed design.

FWIW, I have around 170k miles on my 6 speed transmission and its on the original fluid. 2 Lexus dealers refused to change it and I don't have the appropriate scan tools to comfortably address it, so I'm letting it ride. I tend to think problems creep up when the fluid is changed and something was not done properly, but that a whole other heated debate. If I get 200k miles on it and have to replace, I won't be too upset.

But regarding shift quality on 5 speed vs 6 speed, after about a 5 speed, you really start hitting the law of diminishing returns for most driving. It's probably smoother because there's simply less gear changes. But on the LS, if you feel a huge gear change, I tend to think something is wrong (maybe transmission mounts)

The more speeds added to transmissions is to qualify for CAFE nonsense with the feds and eek out that extra mpg. Next up is 10 and 12 speed transmissions that are going to be a disaster but save the consumer 25 cents a week in gas.

 

My 06 6spd is not rough at all, it just isn't as smooth as the 5spd on 01-03 models nor my wife's 06 ES330 5spd. The 6spd is probably shifting fine for the average person but I expect seamless transition between the gears.

It took some work to find the right tires to restore that Lexus creamy ride and now my attention is turned to what must be done to make the 6spd shift at its true potential.

 

I serviced my 6 speed ls430 in the way that that let the pump pump out the fluid. My transmission had 90000 miles and the fluid was very black but not burned. It shifts perfect. I'll be glad to help anyone else in the Lubbock area. PM me. Rick