Well I've had my car bout a year now i don't really have any engine mods but for some reason i started noticing that when my car get around 30-40 miles an hour and i'm cruising with my foot barely on the gas its seems to try to switch back and forth between gears... it almost seems as if it is trying to slow down then speed up repeatedly. I just thought it was odd and i figured i could see if any of you guys/ girls have had this problem, and if so is it something to worry about?...
i only have 18,231 miles...

 

Automatic? Try the same thing with the transmission out of overdrive.

 

check your wheel bearings to you might have something draging you down.

 

Mine has always done that around those speeds...just drop it in sport mode to eliminate overdrive.

 

@xseveredveganx yea its auto and
@strtrcril87 thanks dude that worked
its it something i should be worried about though? like is it just an overdrive thing and it happens or should i get something fixed

 

it is just the quirks of an automatic transmission. i'm guessing when you're at 30-40 mph, you are on the threshold of when the transmission is trying to determine whether to up shift or downshift because while it tries to use the highest gear possible for best fuel economy, it also tries to recognize desired engine power and acceleration, so it downshifts to give you more power. this is why manual transmissions will always pwn automatics. the driver (a good driver anyway) knows what he wants the car to do and when he wants it, while an automatic is really only guessing and following a program.

i had this problem frequently with my 95 explorer on this uphill right hand bend on I-68 coming out of LaVale. the speed limit was 55 mph, and trying to take this uphill turn while maintaining speed and staying in my lane with a cement retaining wall on one side, and an 18-wheeler in the lane next to you. i would get very frustrated when the transmission would keep changing its mind between overdrive and downshifting when it was critical that the car maintain a steady power output to keep the steering input linear. solution, turn off overdrive while taking that bend.

 

Yep, everyone else hit it on the head. The automatic just can't figure out what gear it wants to be in. Taking it out of OD (3rd) will keep it from upshifting. Just don't forget to put it back in D or 4th when you're back up to speed or your MPG will suffer

 

dude thats perfect thanks... lol cause thats exactly what happens... being though as i got the car as a gift from my grandparents... which i love um for it but i kinda wanted stick shift... hahaha

 

I wish mine was a stick too, but the auto can be lots of fun

 

I definitely have noticed the same thing in my 08. I was worried it was the transmission too and thought about having the dealer look at it but I knew it would be one of those things that "they didn't notice" while driving it. I can't believe that leaving in 3rd is the answer though. This seems like a bandaid to something that could be an issue. I am considering bringing it up the next time I have it in. Mine also seems to do it more right after I start up and I'm leaving my neighborhood but once I've driven for awhile then its not as bad.

 

you guys need to learn about how automatic transmissions work. seriously. it trys to interpret what you're doing and figure out what gear is appropriate. it is a computerized program and algorithm, it isn't psychic. toyota programmed it to be fuel efficient so it trys to upshift as soon as possible, BUT people also want their transmission to be responsive so when they floor it, it does it immediately. so it will be eager to downshift and accelerate for you on a whim. but like i said, it isn't psychic, so when you put in in 3rd, guess what, YOU JUST TOLD THE CAR WHAT YOU WANT IT TO DO! and it does what you ask! what a marvel of engineering! kudos to toyota.

also, on cold starts, the car will hold lower gears longer to keep the engine speeds higher and warm up faster so everything gets up to operating temperatures sooner. toyota did this to improve longevity and reliability. but people probably thing is is annoying to have an engine being louder for 10 minutes instead of having a car that starts breaking down sooner.

the morel of the story is, if you don't like how and when to change gears, get a manual and STFU.

 

Agreed with drax. Read the owner's manual and it'll probably tell you exactly what we've said. Most owners manuals say something like "if the car repeatedly changes between gears, take it out of overdrive" or something to that extent. RTFM and this wouldn't be a problem. It may be several hundred pages, but half of it is pictures and warnings, and each page is only about a quarter the height of a regular letter size sheet. You could easily read through it in three nights if you read a little before bed.

 

My 1985 Pontiac with a 700R4 transmission would surge. I kept it out of overdrive, except when I was on the interstate. That's the only time I'd use it.

 

Leaving it in 3 for driving around is a good idea. I really hate when you moderately speed up to 40 or so then back off the pedal, and the darn tranny hits 4th asap and robs the pickup, then downshifts again.