[Martymart]

I just bought my KIA K5 GT 2023. When setting the cruise on 55, this is what happens: when going up a hill the tachometer would jump from 1and a half rpm's to 2 rpm's. If the hill was steep, it would jump up to 3 sometimes 4 rpm's
I took the car back to the dealer and they checked everything and said it was ok. This can't be right. It only happens when the the car is on cruise control. Has anyone else had an issue with this.

 

[Andrew72]

Google 'why does my transmission downshift to maintain speed?' and let us know what you think... 🤔

 

[Lu1s95]

That is completely normal. It is downshifting too keep your desired speed.


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[Mike_TX]

Dude, if you go up a hill, the transmission has to downshift and the engine rev higher, to make it up the hill. You think it just happens when on cruise control because it's doing it automatically, but when it's not on cruise, you are doing the same thing with your foot on the gas. But the downshifting is completely normal - otherwise the car would just lug down and maybe not even make it up the hill.

You say your car is a GT ... this would be more likely to happen with the smaller 1.6 liter engine. Is your car maybe a GT Line?

 

[neemster]

Dude, if you go up a hill, the transmission has to downshift and the engine rev higher, to make it up the hill. You think it just happens when on cruise control because it's doing it automatically, but when it's not on cruise, you are doing the same thing with your foot on the gas. But the downshifting is completely normal - otherwise the car would just lug down and maybe not even make it up the hill.

You say your car is a GT ... this would be more likely to happen with the smaller 1.6 liter engine. Is your car maybe a GT Line?

They said it only happens when the car is in cruise control. They made it sound as if when not in cruise control the tach jumping doesn't happen. Sounds odd but I'm just going off what they're telling us.

If truly a GT this would mean it has to downshift to maybe 4th gear at that speed? I find that odd as well. In normal mode at 80 mph my GT has no problem accelerating up a hill even when I lock it in 8th.

 

[Martymart]

Dude, if you go up a hill, the transmission has to downshift and the engine rev higher, to make it up the hill. You think it just happens when on cruise control because it's doing it automatically, but when it's not on cruise, you are doing the same thing with your foot on the gas. But the downshifting is completely normal - otherwise the car would just lug down and maybe not even make it up the hill. You say your car is a GT ... this would be more likely to happen with the smaller 1.6 liter engine. Is your car maybe a GT Line?

Yes