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2004 Hyundai Sonata Automatic Transmission Shifting Problem

Hey guys,

So my Hyundai Sonata has had this weird shifting business for the past couple weeks (definitely should have taken care of it sooner but I’ve just avoiding driving it in the mean time). Basically it’s best described as having the clutch be released quickly or slowly in a manual car except it’s an automatic. Every so often it will shift and after that it behaves like either the clutch was released quickly, and jerks, or very slowly so it feels like the clutch takes awhile to fully engage. I know that automatics don’t have clutches, this is just how I’m describing it.

I don’t know much about transmission so the question is whether this sounds familiar to anyone, possibly low fluids or something or if this sounds big and I should take it in asap. Before this started I took the car in for a some number point inspection and they told me that the transmission fluid was too full (Jiffy Lube’s fault if they were right) and they lowered it. It started a while after that so I don’t know which caused the problem.

Any help would be appreciated, I’d like to avoid the mechanic if I can but I suspect that won’t be the best route so fire away.


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Automatics do have clutches - they’re on the inside. And what it sounds like to me is that the transmission is slipping (“takes awhile to fully engage”), the computer is seeing the slip and ramping up the fluid pressure (“jerks” to avoid the slip.

Of course - that is all guesswork.

Did you check the transmission fluid? Look in the owners manual for the correct procedure and do that - like NOW.

How many miles are on it?
Has the transmission ever been serviced? (Sounds like Jiffy Lube did something to it? Bad idea).
Is the check engine light on? Many auto parts stores will read codes for free, and if you get some post the exact and specific code(s) (e.g. “P0123”)

Your initial idea sounds right, it comes and goes so if the computer is changing the fluid pressure maybe the sensor is giving bad readings. The engine light is on but has been as long as I’ve owned the vehicle (couple years, just went over 100,000 in the past month), something to do with an expensive faulty sensor (pretty sure unrelated sensor, but now that I think about it weird the inspection didn’t raise any questions about that?).

I’ll check the transmission fluid asap and see about the error code reading.

Thanks for the help

Yeah - the problem with ignoring the lights is that you don’t know when something else comes up. So do get the codes read and post all of them. It is easy and free at most big box auto parts stores. Don’t assume that whatever they say about the codes is correct. Just write them exactly as they appear and report.

You mentioned Jiffy Lube. Like Cigroller said, bad idea. Besides whats been said about having the codes checked, at 100k miles it’s a good time have the trans fluid changed. Go to the dealer to get that done. From some things I’ve read some auto trans need to have the original type of fluid due to the properties of that fluid and that is what the Hyundai dealer will use. I don’t know if that’s true but the small extra $$ that the dealer will probably charge would be worth the peace of mind to me.

So I went and had the codes read, unfortunately only one was seen and it was related to the problem from before when the check engine light was on (some generic error code, I forgot to actually right it down since it was the same one the car has always had). I’m taking it in today to have a guy take a look, maybe have him read the codes off of it again so I can post it.

Thanks for your help again, much appreciated

“they told me that the transmission fluid was too full (Jiffy Lube’s fault if they were right) and they lowered it. It started a while after that so I don’t know which caused the problem.”

The level of the fluid is apparent when you look at a dipstick, but what is not apparent to the naked eye is the type of fluid that was used to fill/overfill that transmission. If the poorly trained kids working at Jiffy Lube did not know how to fill the transmission properly, there is a high probability that they used the wrong type of fluid in it.

In fact, there is a very high probability that Jiffy Lube doesn’t even keep all of the various types of trans fluid in stock. Just as they like to use the same type of oil in all of the cars that they service, they likely use the same type of trans fluid in all of the transmissions that they “service”–and that can be fatal to a transmission.

If I was in your situation, Black6dog, I would take the car to an independent transmission shop, and have the fluid & filter changed a.s.a.p. If you are very lucky and if you have lived a good and virtuous life, that just may undo the damage that was done by going too long w/o a trans fluid change and/or the use of incorrect fluid.

Just as many people fall for the advertising of unskilled places like Jiffy Lube, many folks also fall for the advertising hype from chain transmission shops, like AAMCO, Lee Myles, Cottman, Mr. Transmission, etc. Unless you want to be sold a rebuilt transmission–whether you actually need it or not–you should AVOID all of those chain trans shops and look for an independent trans specialist who has been in business for at least 3 years. The price will be the same–or cheaper than at a chain shop–the diagnosis is more likely to be honest, and the workmanship will be much better.

I’m not an expert on transmission, but you might want to check out this site:

. The only fluid you should use is ATFSP3 any other fluid will not protect your car properly. Who knows what Jiffy Lube used. I would have the tranny serviced at the dealer. Ait only cost me $80 for a new filter and new fluid on my 09 Camry. I could do it myself, but fluid, filter, gasket, and time would cost me more.

This thread is 3 months old. Let it die a natural death.

Sorry. Popped to the front page. Needs to be closed.

I just got mine on the road and it now does that, I don’t have 1st or 2nd gear. Did you ever find what the issue was ?

I have an 04 Hyundai sonata it’s an automatic v6. I had a problem with the transmission shifting hard. when I lift my foot off the would shift hard into gears up and down. So hard that you can actually feel them. but it’s through an O2 sensor code and a throttle positioning sensor code. and I change the tranny fluid because it needed to be changed. come to find out my problem with with it was the hose from the throttle body to the air filter box had a slice in it. well I used some electrical tape and pushed it together to close the slice and electrical taped it up for now. and after that no problems out of it.

You should take the car to a Hyundai dealer for a complete transmission service. There is a chance that iffy lube, in addition to over filling the transmission, used the wrong fluid. And I hope you’ve also learned not to drive around with the check engine light on. Frankly, you’ll be lucky if you come out of this without needing a new transmission.