lexus-is2

My 2006 IS250 has 160k miles on the clock. I posted that about a year and half ago the dealer replaced a solenoid on my transmission and add new transmission fluid to replace the lost fluid. Since then the car has been shifting not as smoothly, I read in many places that it must have been not put with the correct amount of fluid. So took it back to the dealer and mentioned this and they agreed to look at it, they agreed it wasnt shift correctly but said it has the right amount of fluid, so they just upgraded the transmission software. A year on, it has just been getting more and more jerky and this morning it kept flicking between neutral and gear while driving and jerking like crazy.

The is no engine light or anything but the transmission is feeling really jerky. I was driving and it kept going to neatral and gear back and forth for a while and felt like i was hitting a car everytime and getting whiplash. I put it on snow mode, and it still did it for a while but then calmed down and was able to calmly drive to work. But the entire journey the N and the D light was on together. and while this issue was happening, it wasnt switching to S mode.

Any ideas what this can be? Can insufficient fluid cause this?

xanderES

iTrader: (8)

Honestly if your car was switching from N to D I wouldnt even drive it. Thats how you destroy your transmission. Id definitely just go back to lexus and see what they can do. After all, you can show that there has been a considerable issue with it ever since they "fixed" it.

lexus-is2

That's what I was worried about, it was jerking like crazy for a minute or so as it just couldnt make up it's mind between N and D. Then managed to drive it fine in snow mode all the way to work which was about another 45minutes drive away. So called the dealers and they agreed to have a look at it later in the day. So I left work to get to the dealer which is about an hours drive. Was expecting similar issues to arise or some kind of issue, but no it's as if there was no problem at all and car drove without doing this all the way to the dealer. Strange thing is that if a car was to be in gear and then a person puts it in N and the back in gear back and forth, it shouldnt jerk should it?

The technician at the dealer test drove it and couldnt replicate the issue, he drove it hard and at first he thought maybe but couldnt find any signs of slipping. While i waited they put it on the ramp and inspected and plugged in the diagnostics tools and could not find anything wrong. But I just couldnt accept that as an answer because something is definately wrong. A jerky shift i can live with but what happened this morning scared the crap out of me. Driving on the freeway and the car is jerking and making gear switches.

They've agreed to keep it overnight and do a cold test drive. But I fear they wont find any symptoms.

What is the symptoms of slipping?

VTsuckah

iTrader: (1)

The rpms with keep increasing, but you will not feel the car accelerate much at all.

lexus-is2

So it doesnt seem to be that, because never had rpm rising and no power.

Any suggestions on what to say to the dealers if they cant find anything? because something is definitely wrong

Mike_1GO

iTrader: (2)

since the problem is intermittent, I believe its electronics/software related. almost like there is a short somewhere. if lexus cannot replicate the issue, then the next time it happens with you, I would drive straight to the dealer and not to work if possible

lexus-is2

When i had the solenoid replaced and the work carried out at the dealers it cost a fortune so dont want to keep throwing money at the transmission specially considering it has done 160k miles.

If dealer doesnt find anything, might asking them to try and do a complete transmission flush help?

I've come across 2 second hand transmissions, one from a 2011 at 17k miles and another from a 2007 at 48k miles but the 2011 one is 1.5k whereas the 2007 one is 550, huge price difference. If i go for a second hand transmission which comes complete with the torque convertor and all the solenoids, i assume that the sump and everything will still be connected and holding original fluid, so will new fluid still need to be added?

lexus-is2

Dealer has had the car for the whole day and havent been able to find anything. they've run the diagnostics and cannot find anything at all. So the only thing they are saying now is that they suggest to keep driving it and if it comes back, they're hoping a code will register at some point that will help them diagnose the issue.

back when my solenoid issue came up which required the solenoid change, for many months i was getting intermittent lags. Basically car used to drive normally and all of a sudden and not always, once warm i would get a huge lag almost like a DBW delay. This was fixed by turning car off and on, then after good few months an error code finally came up indicating the shift solenoid issue. Wondering if it may be something similar and maybe another shift solenoid getting stuck. But will a stuck or sticky shift solenoid cause the N and D switching automatically?

lexus-is2

So i picked up the car on Saturday was fine but to me the gear changes just felt way to jerky compared to usual. Anyway, so as the dealership advised. Drove it to work, all ok. On the way back home however, i am about 10 minutes away from home and as i'm coming to a stop i get a very sharp jerk almost like i did an emergency brake, thats exactly the symptom i had last time. So looking at the dash and bingo the neutral light starts to flicker. So basically D and N is now on, so put it in snow mode and parked up on the side road.

I stopped the car and when i put it on R it's fine but as soon as I put it back on D, i get a huge jerk (not the usual soft jerk, almost like i'm being rear-ended) and N and D are lit together. So tried putting on P and then trying again, but still same thing. So tried turning car off and on and this time i got the check engine light and VSC off message. So put it on snow mode and slowly drove home which was about 5mins away. Snow mode seems to work even though both N and D get lit together.

So i got home and plugged in my OBD scanner and read the code and it reads: P0705 - Transmission Range Sensor "A" Circuit (PRNDL Input)

Going to call the dealers first thing in the morning.

I read the lexus tech doc on this code, and it states the following:

• Test the PARK/NEUTRAL POSITION SWITCH ASSEMBLY - if not good then replace
• If OK then test the TRANSMISSION CONTROL SWITCH - If not good then replace
• If OK check HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH - ECM) - If not good REPAIR OR REPLACE HARNESS OR CONNECTOR
• If OK REPLACE ECM

Gville350

iTrader: (10)

^Sounds like the dealer didn't test out the car thoroughly enough after the "fix" was done, if even at all.

lexus-is2

Am i correct in assuming the position switch is attached to the transmission itself and the control switch is referring to the actual lever switch that is inside the car? So, they will first need to test the switch outside the the car and if thats ok then the inside one?

I've been telling them it just is not feeling the same and they just cannot seem to help. Lets see what they say tomorrow.

Gville350

iTrader: (10)

Man, your guess is as good as mine. Crossing-fingers, I've had no troubles with my auto trans; so I've not yet have had to do any in-depth research on them.

lexus-is2

Just an update.

Heard back from the dealer, apparently the neutral position switch is heavily coroded and so are quite a few other connectors which will need to be replaced as a loom repair instead of a loom replacement. All in all the cost is been quoted at just over 1k, they claim it is approximately 4 to 5 hours labour. The car has never been subject to any water damage or any water related incidents and to be honest we've never even had snow thick enough to even reach these connectors and the switch. Seems to be a very poor design in my opinion. It's just very odd that the connectors and the neutral position switch can all corrode at the same time. Also, if these components are that important, should they not be better protected from the elements? The frightening thing about all this is that because of this the car decides to start jerking like crazy at 50mph which to me felt like harsh breaking. I could have easily been rear-ended if someone was close to me. If components like these are so essential, should the car not just go into neutral and allow you to come to a stop rather than shifts gears back and forth by itself.

kiryu

Wow sounds horrible, sorry to hear... Yes it's definitely a safety hazard the dealer should definitely fix it up before giving it back to you

My dealer told me the IS tend to have transmission problems at above 150k... Hope that's not as common an issue as he claimed...