I drive a 2007 Toyota Highlander, 4 cylinder/automatic/116,000 miles. I’ve noticed that when it gets really in the Winter I have a problem. Here is what I’ve noticed: I will start up the engine and let it run for 1-2 minutes (at start up idle the engine has a loud hum and after a minute or two it finally levels off). Once I start driving and gets to about 3rd it seems to get stuck there and doesn’t change up until a minute later, all the while emitting a loud hum. It will eventually change up to the next gear if I wait long enough, or if I slow down and start again from first gear, or when the engine finally warms up. Other than that the vehicle runs great. I just had the battery replaced a week ago. What do you guys think is causing this, or what should I have checked first? Thanks for any suggestions.
My guess is that it is by design and won’t let it go above 3rd until it is warmed up. This keeps the engine running faster, warms it up faster, gets it to closed loop faster and thus saves fuel - which I believe is the purpose for programming it that way.
As for the hum, you’d have to be more specific. Lots of things can hum. My car is doing it right now as it warms up - the bumper cover is a little loose and takes on a nice resonant vibration right at the warm up high idle. So you’ll want to see what you can do to get some idea of the location of the hum and maybe think and say more about what kind of hum it is. (Electrical-type? High pitched? Low pitches? Changes with …X? Stuff like that).
cigroller, I appreciate your comments. there are no loose elements in/around the car. Everything is nice and tight under the hood, inside the car, etc. This is a loud, high-pitched hum that comes from the engine which was not there when the car was newer. I’m wondering…If what you’re saying about the design is true, wouldn’t the car be doing that whether the car was newer or older?
One thing I did not mention in the original post is that when the car does shift out of 3rd, I can hear “clunk” sound as if a knot had just loosened or something like that
What kind of climate are you in? Is it among the areas of the country that have had some of those colder than normal temps? That could matter to either case.
As for the hum, the first thing I would do is check the power steering fluid and also listen at the reservoir/pump to see if it is humming. Cold will not only annoy older pulley bearings but it will also affect the power steering fluid level. It expands when it gets hot. So if it is a little low, it might be too low when cold (thus making noise) and then within range once warmed up. If you find that you’re low, however, it does mean that you have a leak someplace.
On the shifting, now that you say it sort of “clunks” out of 3rd gear, that could be a different story since it is not normal to get any kind of clunk. First thing is first - also check the transmission fluid level. It goes the same as the power steering - lower when cold and expands when hot. If it is too low it will create very noticeable issues, and on a slow leak those would often be seen first when cold. The transmission will start cold with the fluid below the acceptable range of fluid level and then make it to an operable range once warmed up. (It still means you’re low on fluid either way. Your stick will have cold/warm/hot levels on it).
The transmission also has a pump that will whine (and be called a high pitched hum) if it isn’t happy. Has this transmission ever been serviced? Are there any kinds of warning lights on the dash?
Anyway - short story is check the power steering and transmission fluids first. If you find no sign of an issue there, then personally, I’d want to have a pro from a locally owned, reputable transmission shop take it for a drive from cold.
Cigroller, as usual, appreciate the professional input.I live in Maryland where some winters are mild, almost spring-like at times. This one has been extremely brutal, mostly below zero for most of this winter so far. All of what you’ve said here makes sense, so I plan on checking out the fluids first and see what happens, then check out the transmission if the problems persists. My first inclination was to take it to the transmission specialist first which could have cost me a hefty sum and probably no resolution (that’s usually the case around here).So you may have just saved me some dough. I will update with my progress. Thanks
Car shifts into reverse fine? And 1-2-3 shift is good? But no overdrive? You need to hit 40mph or so for OD. Around town, u may almost never see OD use?
How long since the trans fluid was changed? More than 30K miles?
Has the thermostat ever been changed?
These are two relatively inexpensive things to try.
As far as I know most if not all Toyota auto OD transmissions will not go into OD until the coolant has reached a preset temp.
This is right from page 146 of the 2007 Highlander Owners Manual.
Always turn the overdrive on for better fuel economy and quieter driving. If the engine coolant temperature is low, the transmission will not shift into the overdrive gear even with the overdrive on.It is the same with my 2002 Camry which has the same engine/trans combination. 2AZ-FE (2.4L)/U241E (4sp.auto)
My fiance and her step mom both own 2007 toyota yaris’s. They have the same transmission behavior. It wont go into 4th until it has fully warmed up. It must be programmed in. I drive the yaris quite a bit myself and it is annoying when the trans does this, but judging that this seems to be common it must be a programmed thing.
2007 Yaris owners manual page 126:
Always use the “D” position for better fuel economy and quieter driving. If the engine coolant temperature is low, the transmission will not shift into overdrive gear even in the “D” position.
Get your fiance, her step mom, and you since you drive the car quite a bit, to read the manual. Yeah it is supposed to work that way. People will read the owners manual for their stereo, TV, Smartphone, but won’t open the instructions for what is probably the second most expensive thing they buy. I know it’s a boring read, but there really is lots of good info on the care, feeding and enjoying the creature comforts of your new toy.
BTW I think that same paragraph (almost verbatim) is in every Toyota Owners Manual that covers a vehicle with an automatic overdrive transmission.
Yes folks - we covered the normal operation of limited upshifting when cold at the very first post in the thread. The “behavior” is new and is accompanied by a hard shift. Perhaps it’s only the hard shift that is new and that’s why stuck in 3rd is only just noticed. Who knows. But the “normal” programmed limited upshift when cold was covered out the outset. Now where did I put my “dead horse” graphic?
Left friends house the other night. Got on highway. 3k rpm? Had shifter in 3! Doh.