Glad to hear your 6 is now as smooth as the 5. This was a drain and fill? I had one done when I bought the car. Plan was to drive 1k (which I've done) then do another. Sounds like it's time for a trip to LOR.

 

tallca, I went in wanting a drain and fill. Service manager at Lexus of Roseville said he'd like to take a look first before doing any work that may be unnecessary. I took out a loaner and few hours later learned that they had to drain out an extra quart of tranny fluid, but that was it. They didn't have to add any in because it was over filled the last time I had a drain and fill a few months back (performed by my independent mechanic). Service manager said the fluid color was perfect and better that it had too much than not enough. After they removed the excess 1-quart, the car has been shifting great and no longer does the lurch/lunge when going from Reverse to Drive.

 

Pop quiz since I've driven sticks most my life....if one sees a LS with 130k, 170k, is it very likely that the tranny was never repaired? Is overhauling an automatic a thing of the past? Being sealed with no dipstick does IMHO imply there is little maintenance, that there is no reason to be adding or topping off, since it cannot be checked. I know I should read the manual, but is there any recommended change interval at all?

 

That's interesting. I had my independent mechanic do a drain/fill right after I bought the car. Now I've got the slight reverse to drive "lurch". I've driven 1k miles so it's time for the 2nd drain/fill. I'll have LOR do it to make sure my indie got it right. I'll also have them check the car to make sure everything's good. LOR knows the car because they've done all the service work for years.

 

If it helps, Brent Colley, at LOR, was the service manager that helped me. He used to be a master technician for a number of years before.

I've been making up excuses to run errands just to drive the car more and literally just came in from the garage after another non-essential errand. The tranny is also smoother going from Park to Drive/Reverse when getting back into the car. Nothing shakes now and the car just stays still when I put it into Drive or Reverse. I just don't understand how draining a quart could make such a differnece, but I love the car even more now and have put aside my desire to "upgrade" to the 460L. I still want a 2011/2012 460L but the urge isn't as strong anymore, seeing as how well the LS430 is operating now. The lurching was bad enough that I was convinced I needed new engine and transmission mounts replaced, but I do not feel that way anymore.

 

Thanks for the name. LOL at reading that you're making up excuses to drive. Same here. It's getting worse tho. The 5 minute in town shopping trip the other day turned into a 35 mile drive. One of these days, it's going to be a several hundred mile overnighter. Glad to hear your 430 experience is starting to go well (and that it was so easy to solve the problem. I may buy a 460 at some point but not in any rush.

 

So I wanted to give an update with my transmission shifting after Lexus of Roseville drained 1-quart out. The shifting definitely is smoother and more "Lexus-like". It has been a week since I first experienced the hard downshift that felt like getting rear-ended when coming to a stop, but today it recurred twice. I can almost reproduce it at-will now. It happened today as traffic was slowing and I braked to a stop. Traffic was picking up again so I didn't come to a complete stop and was lifting my foot off the brake at about 3 MPH and that's when I felt the hard slam of the transmission. I looked in my rear view mirror just to make sure the truck behind me didn't just hit us (had my daughter in the car seat).

All this hard downshifting only appeared after Lexus of Roseville drained the 1-quart out. I am not pointing fingers at the dealership because the transmission is smooth at all other times. I am simply stating the timeline of the issue, plus my research points to the problem possibly being caused by the ECU. Since mine is an 06, the "rough shifting at low speed" TSB for 04 models doesn't really apply. I find it odd that the hard downshift occurs as the car is almost at a stop and when I'm lifting off the brake, similar to when you pump the brake pedal to cancel out nose-dive. When the hard downshift occurs I have not even applied any gas, my foot is still on the brake. I have found the following links that make mention of the phenomenon in both LS and GS models and both concluded replacing the ECU fixed the issue. Some had to learn it the hard way after Lexus recommended a $5,000 tranny replacement, only to have the problem continue with the new tranny!

Am going to have my independent mechanic take a look when he can fit me in his schedule because I know he'll work with me to analyze the issue without repeated diagnostic bills. It is really strange to experience this issue because the tranny is operating so smoothly in every other circumstance. It also seems odd to take this long for the tranny to "learn" how to downshift to 1st gear with the new tranny fluid level. The hard downshift to 1st doesn't happen every time I come to a stop. It seems to occur if I'm slowing down but ease off the brake just before a complete stop. Very odd behavior.

http://repairpal.com/poor-shift-qual...low-speeds-550

https://www.clublexus.com/forums/gs-...to-a-stop.html


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I personally don't believe a faulty ECU has anything to do with your problem. The fact that the transmission is having big issues right after they drained the fluids means somebody screwed up. They've already messed up pretty bad the first time by overfilling by a quart, I still think they have filled it by an incorrect amount or made some other mistake.

The coincidence of an ECU frying after they changed the transmission fluid and only effecting the transmission of the car is like the odds of getting struck by lightning.


I would take it to another Lexus dealer and tell them you believe they made a mistake. You probably want to have it towed if it feels like you're being rear ended every time you drive it asrunning it that way could damage it. My only concern with an independent shop is if they have the right Lexus Techstream scan tools that are supposed to be used when you change the transmission fluid and do they know how to use them?

 

Thanks, BradTank. It does not happen every time and I couldn't reproduce it today. It happened 3x in the first two miles after the tranny fluid was drained at the dealership (the overfill was performed elsewhere). The problem did not show up again until a week and 300 miles later (yesterday).

 

This bothers me.....and having little experience with autos, I dunno if anybody should, or should not, touch, since it's sealed. I will likely not proactively do anything with the tranny, whatever the book says....(whereas I don't care if the coolant goes 100k, I'll get some new stuff in there and let the dealer flush at 82k), and I don't even need to go 50k to the next change)....

 

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I'm just going off of this post, it seems like it's something you can make happen every time you drive it.

 

That's definitely bad wording on my part, Brad. It does feel as though I can reproduce it at-will because I thought I recreated it yesterday seconds after it first unexpected occurred. Since yesterday though the tranny behaves fine again through multiple slow-downs-and-speed-ups in traffic. Just not sure what to make of it. I hope I did not give the impression the the car is undriveable. My apologies if I conveyed that message.

Johnhav, I am starting to wish I had just left the tranny alone instead of seeking out smoother shifts. Sigh.

 

I would suggest you take it back to the Lexus dealer. They will probably remember you. Tell them you still think something is wrong. I would also request one of their techs takes a test drive WITH YOU. Then, cross your fingers, drive and try to reproduce the slamming.

 

Father, sorry to hear about the problems! Hope you can find a solution. Did LOR do a drain/flush or just remove the excess fluid?

On mine, first drain/fill was done by an indie 1,500 miles ago. I just had Lexus of Roseville do the 2nd drain and fill. Brent said fluid looked good and wasn't discolored. I'm not going to do this again for at least 50k miles.

Now shifts quite smoothly. In lower gears and moderate acceleration, have to check tach to see shifts. Still can't beat the "invisible" 5 speed but my 6 speed is now "Lexus smooth". No more slight clunk with reverse>drive shift.

I now know the Indie overfilled more than 1/2 quart and used wrong access. They also did the job in less than an hour so maybe they didn't measure the temp. I know it's possible to DIY the change but seems like getting the correct level means using temp. Just replacing with the same amount of fluid may not be accurate. Asked LOR about doing a total flush. Got the standard answer that it may cause problems w/ an older transmission.

 

Any problems if you manually shift? My first post about 5 vs 6 smooth included mention of driving in slow traffic. Trans up/down shifts were quite noticeable end not very smooth. It will be interesting to see I get the same results after reflash and 2 drain/fills. My LOR (Brent) experience was excellent. Hope they take care of you