vinz8

Hello,

2006 IS350 with about 205,000km (about 127,000 miles)

Up to date with all maintenance, changed 3 of the transmission solenoids + full transmission fluid changed last year. Last year I was getting intermittent CELs for the shifting solenoids, and replacing 3 of the transmission solenoids have somewhat helped.

My problem: When I'm driving on the highway/freeway, whenever there is sometimes a curve when I need to brake, the transmission will downshift to 3rd, and afterwards it will be "locked" to 3rd gear and will NOT upshift. Even when I change it to M (manual shifting) mode with the paddles, it will still be in 3rd gear, and revving up to 5k+ RPM. I'm in the regular mode, not the Power mode.

It's ONLY when I come to a full stop (either a red light or pull over to the side of the highway) when the computer resets itself or something, and then it can drive normally again, and it will drive and shift normally past 3rd gear. No CEL has come up, and sometimes when it does, it goes away very quickly (in about 2-3 driving days)

Sometimes when driving at high speeds and at a curve, the RPMs drop a lot, then the computer shifts back up and the revs go high again.

Any thoughts/advice/help? I checked on forums, but no one has an exact answer - answers have varied from buying a new transmission, getting a new ECM (which happens to mostly GS300s), replacing transmission solenoids (which I already did last year), and maybe crankshaft sensor? I have no solid answer to resolve this

Also, when I'm coming to a full stop, the car stops in 2nd gear, and when it is stopped, it drops from 2nd gear to 1st and the entire car lurches a bit (as if it was hit from behind). Still haven't gotten an answer on this one

Thanks in advance.

qnt469

I have similar problem as you have 2 months ago. Basically what I did was laying out a step by step process to personally diagnose the problem and fix it. Here's what I can give you as far as advice after going through what I did.

1. Check your fuses. It maybe an inconsequential process relating to the gear shift but It doesn't hurt to check and make sure.

2. Check your transmission oil level and make sure it is at the exact required level. During my many times of slowly changing out the new oil to dilute the old oil instead of flushing the transmission. I notice that when I got lazy and not perform the check process properly. I end up with insufficient amount in the system and the car would jerk and behave erratic during gear shift. Having a bit more didn't seem to hurt as much as not having enough. Having the right amount makes the gear shift smooth and feels like new.

3. Check the solenoids again when you drop the pan to dilute your transmission if you have not already done so by now. There are 9 solenoids total. If you changed 3 solenoids and left the oil dirty since the last time you change them. Chances are the others may have clogged up or the same 3 may be clogged up. In any case being absolutely sure of oil and filter being fresh in addition to having all 9 properly working solenoids are the easiest and least expensive options.

4. If all of the above steps check out so far and you're absolutely sure all is in order. You have to move to the valve body diagnose. I have not done so myself but I'm sure many of the members here have experience in them that can help. From what I've been having to deal with on my own car. I'd say it's best to remove the transmission since it's difficult to work laying down when playing with the valve body.

5. If that check out perhaps next is the torque converter that needs to be replace. Of course this will required transmission being dropped down unless there's some other way that I don't know of.

6. If that is replaced and you're still having issue. Then it's time to get a replacement transmission or rebuilt it yourself. By the time you get this far, I'm sure you'll be more informed about transmission than I do.

7. Of course there's always the alternatives. Bring it to the trusted experts. Dealership is another expensive option.

If you got any questions. I'll share with you what I know. Good luck~

2013FSport

iTrader: (2)

One has to question what actually failed previously.
Solenoids failed electrically or did they jamb, or where they plugged?

There are other options too. Components of the valve body do actually fail. There are external sites listing repair services and tools to fix worn components.
Do a search on A760E valve body repair. There is way more to it than the solenoids.


qnt469, nice post...

qnt469

I guess there are 3 cause of failure I can think of.
1. The spring in the solenoid had fatigue failure where it just gave up.
2. The fluid channel got jamed with metal shavings
3. The electrical coil got damage some how due to over load or broken wire.

As for mine I have no clue. I am guessing the fluid channel got stuck since I hear nothing when I shook it.

Joseg510

I have a 2006 lexus is350 and i have had a clicking noise occur since i got my car.My car has 131k miles. Everytime the car is running and its in 4th or 5th gear i let go of the pedal and i start to hear a clicking noise occur. Anyone knows what this could be? My transmission has been kicking lately im just wondering if the clicking sound can be a grind?

qnt469

If the clicking happens when it tries to downshift. It maybe early sign of failure. The electronic tries to compensate for something that fail.

Early failure I’ve seen on my car was when I take off from complete stop, the gear slip when it shift up to the next. It happen here and there. Then gradually happen more often until it stop shifting at all.