2005 Toyota Sienna XLE
89000 miles
3.3l dohc v6 w/vvt-I
Automatic transmission
When driving on the freeway (with or without cruise control on) and doing 2200/2300 rpm and then come to a slight incline and the rpms increase to 2600/2700, then the whole van shakes and seems to not have much power. The steering wheel does not shake. If the rpms increases to above 3000 then everything is okay. If you go from 2200/2300 rpms to 3000 everything is good. It also happens at lower rpms, but happens when there is a slight incline and it needs a few more rpms, but not an all out punch. Like getting on the freeway with a uphill on ramp, or even a long stretch of road with a slight incline. Seems to happen when there is a strain on the engine but not enough to cause it to jump to a real high rpm. I first noticed it at about 87000 miles. Driving in Kansas and there was a high winds and lots of dust. At that time I thought it was just the wind.
Toyota dealership looked at it and could find no service bulletins and could not duplicate symptoms. (we are in Florida and very few hills) It has happened to me here but very often or as serve. It starts to shake but then comes out of it.
Service
80800 miles
Resurfaced rotors
Adjusted back brakes
Flush and new fluid in transmission ( had same service about 40000 miles earlier)
Injector service (cleaning)
Power steering flushed and new fluid
Rotated tires
76000
Air filter changed
75000
Replaced 2 belts
Have had oil changed every 4000 to 5000 miles.
Presumably if your check engine light was on you’d mention it? Did the Toyota dealership do a full scan including a check for any transmission codes?
It sounds to me like a torque converter clutch (TCC) problem. Cruising at mostly steady throttle the engine & transmission lock together and both turn at the same speed. The torque converter clutch is what does that. When you either accelerate somewhat substantially or brake the TCC should unlock. You may be getting shudder from a TCC that isn’t holding properly under light acceleration or not unlocking when it should. The problem can be hydraulic, electronic, or mechanical.
Do you know whether or not the dealership specifically looked at that possibility. A skilled transmission technician with the right scantool could figure this out. If the van isn’t under warranty you don’t need to use the dealer.
You are right there is not check engine light or any others on. I talked to the Toyota repair shop, and they did do what they call a health check. They did not see any indication in the computer of any thing wrong, that included looking for transmission codes.
If I decided to have a transmission technician use a scantool, do you have any idea what that might run?
Thanks for the help
What you would do is find a local, owner-operated transmission shop. I.e. don’t use the corporate chains. Maybe ask around among people you know about local shops to see if you can gauge which seems to be best.
Then just give them a ring. Some shops will actually do a once over for free. Most commonly they will charge an hour’s labor or so. I had the basic diagnostic stuff done recently at a local shop and it was $65 (1 hour at $65 their hourly rate). A lot of the time they also basically put that diagnostic charge toward repair work if any is deemed necessary.
I wouldn’t read much into the lack of codes or the dealer not finding anything. The computers tend to be more tolerant of misbehavior than many people think. (I currently have a TCC problem and knew it 3 weeks before the computer “said” anything about it).
Anyway, I would think about one of two things right now. One is that I’m just guessing. I haven’t driven the van and there are quite a few other possibilities. I’d hesitate to even go spend $65 on a transmission diagnostic if it turns out that you need a new fuel filter or spark plug or something. I didn’t go to basic maintenance items to start since I just assume that the dealer would have been happy to use this as an excuse to sell these kinds of things to you if they were even close to needing attention. (It is also true that your description fits a TCC problem well).
But the second thing is that you mentioned 2 transmission “flushes” (at 40 and 80K). Did either of these include a new filter? If you have never had the pan dropped and transmission filter changed, then I would actually take it to a local transmission shop and ask them to do that. While its there have them check it out. In that case they may charge nothing extra. This would sort of waste your most recent “flush.” But it really should be done each time your transmission is serviced. (But use the search function here to find lively discussions of how one should service a transmission).