[AthleteRob]

Hi guys,

I'm hoping to get your opinions on something. I have a 2011 Optima EX (2.4L automatic). I have about 230,000km (143,000 miles) on it. My dad and I have maintained it over the years and I just got the engine block replaced for free in October 2021.

For the past few months, I've noticed the transmission feels a bit laggy mostly when downshifting gears. For example, it'll take a second or two longer to change gears. I had a transmission flush done last month but the downshifting still feels the same. The "check engine" light is NOT on. Do you guys think this is a sign that the transmission is starting to fail?

Thanks for your inputs!

 

[bigbxsallday]

Slipping is the sign of potential trans troubles. Slower shifts are not as serious a problem as slipping.

Are you sure the correct fluid was used?

 

[KingFatty]

How many miles have you put on since the flush? I think the trans needs time to re-learn if the viscosity is different, but I'm relatively ignorant on the details.

Isn't there a way to use a scan computer, or other technique, to force the transmission to relearn for the new fluid?

But agreed, you should find out exactly what kind of fluid was used in the flush.

 

[AthleteRob]

Slipping is the sign of potential trans troubles. Slower shifts are not as serious a problem as slipping.

Are you sure the correct fluid was used?

Thanks for your reply. I'll call my service advisor at the Kia dealership I go to and find out. It's also the first flush done. The issue seems most noticeable when driving on the highway after releasing the gas before applying pressure to the brake pedal. I just realized that maybe it could possibly be happening due to "engine braking"?

 

[AthleteRob]

How many miles have you put on since the flush? I think the trans needs time to re-learn if the viscosity is different, but I'm relatively ignorant on the details.

Isn't there a way to use a scan computer, or other technique, to force the transmission to relearn for the new fluid?

But agreed, you should find out exactly what kind of fluid was used in the flush.

Thanks for your reply. I've probably done less than 600 miles since the flush so it could be happening because it is re-learning as you say. My mechanic mentioned there may be some jerkiness in the shifting for about a week but it's been a month now. When I drove today, I only really noticed it on the highway and mostly after easing off the gas before using the brake. I'm going to try and get a hold of my service advisor at Kia and find out.

 

[Robertbweltzien]

A scan tool analysis of the trans is definitely indicated. Had the fluid ever been replaced before the flush? If it was and if it the fluid in it before the flush wasn't too dirty then your issue is more likely to be a computer relearn which should resolve in a couple days driving or can be fixed by a mid level scan tool reprogramming. If the fluid is original then the flush probably and unfortunately hastened the transmission's demise by stirring up particles that lodge in the tiny hydraulic passages. That is typical of all automatic transmissions both recent and old; when very old, dark and oxidized fluid is replaced with clean, slippery new fluid the trans often ends up slipping, or shifting harshly and late. If the latter is the case then the shop definitely owes you a new tranny!

 

[AthleteRob]

A scan tool analysis of the trans is definitely indicated. Had the fluid ever been replaced before the flush? If it was and if it the fluid in it before the flush wasn't too dirty then your issue is more likely to be a computer relearn which should resolve in a couple days driving or can be fixed by a mid level scan tool reprogramming. If the fluid is original then the flush probably and unfortunately hastened the transmission's demise by stirring up particles that lodge in the tiny hydraulic passages. That is typical of all automatic transmissions both recent and old; when very old, dark and oxidized fluid is replaced with clean, slippery new fluid the trans often ends up slipping, or shifting harshly and late. If the latter is the case then the shop definitely owes you a new tranny!

Thanks for your reply. It was the original fluid but I was feeling the downshifting and some upshifting lagging before the flush. Upshifting is better now but the downshifting is still noticeable. The car is in the shop now for tire replacement but I will bring up the reprogramming of the transmission with my mechanic!

 

[Robertbweltzien]

Thanks for your reply. It was the original fluid but I was feeling the downshifting and some upshifting lagging before the flush. Upshifting is better now but the downshifting is still noticeable. The car is in the shop now for tire replacement but I will bring up the reprogramming of the transmission with my mechanic!

I hope they can resolve your transmission issues satisfactorily. Good luck!