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Greg, Technician
Category: Kia
Satisfied Customers: 7347
Experience:  Hyundai and Kia tech
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I own a Kia Sedona auto gs 2008 which has a problem when towing

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I own a Kia Sedona auto gs 2008 which has a problem when towing a caravan. After approx 2 hours without warning the revs shoot up to around 3000 and it then goes into limp mode.
I have had 3 diagnostic checks (which show nothing) and a larger oil cooler fitted at a Kia garage.
The problem is still persisting and i feel that it is dangerous as the fault occurred on one occasion when i was overtaking a lorry. Any ideas what may be causing this problem?
Name isXXXXX goal is to provide you with excellent service – if you feel you have gotten anything less, please reply back,

Is it possible the transmission is dropping out of top gear to a lower gear or are you loosing total pressure and have no responce from the transmission .
Is the check engine light ON or the AT warning light on when running or when you have this problem .

Rgds Greg
Customer: replied 4 years ago.

When it happens there is a loss of power, i ease my foot off the accelerator as it happens so suddenly and i don't want to cause any damage.

I select neutral and then back into drive as this temporarily clears the fault and allows me to find a safe place to pull over.

No light ever shows (engine or warning light).

I have had the gearbox checked by a specialist and he couldn't find any fault.

As stated previously, 3 diagnostic checks have been carried out and nothing shows. The car is ok when not towing.

Hi Bob. This is a difficult problem to solve when there is no malfunction codes to assist you with what may have gone bad... This is what i do in situations like this if i'm sure its a transmission issue . If the transmission has not been drained and replaced in the last 30,000 miles i would flush and changed the fluid . Be sure to use only diamond SP III ATF fluid on this transmission. Check first before replacing the fluid that the level is good and the condition of the fluid is clean and still a nice light Red to very light Brown. if dark brown to black then this is a sign of internal damaged .. If the fluid is old and has never been replaced then do this first ,this is worth the trouble to do and check as this could be your problem, if you have still the same issue after replacing the fluid then you will have to do a test drive with the caravan on tow with a transmission pressure gauge fitted to see where you are loosing fluid pressure. If no codes or any other indications then this is your best way to repair your problem the cheapest way. Need further assistance then please get back to me . My goal is to provide you with excellent service – if you feel you have gotten anything less, please reply back with the reply box below and not the poor or bad service button , For further assistance there is no extra charge after accepting. Rgds Greg

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Customer: replied 4 years ago.

Hi Greg, have just been to Burton on Trent kia today .Nothing showing on the diagnostic check ,the tech has emailed kia tech department for any help,but he did say the gearbox transmission should be changed to diamond sp3 a.t.d.which is what you have said.The techs name at B.O.T is Andy Blackshaw

regards Bob

Hi Bob.


Thanks for getting back .


Did they change the fluid for you ??



One more thing that could cause this issue is fluid level to low .


Fluid level should be checked after 1/2 hr driving, then check with transmission in "P"

the fluid level should be in the HOT range if lower top up to correct level .





Customer: replied 4 years ago.

Hi Greg, no they did not change the fluid because its not one they stock plus awaiting info from kia.Fluid level ok. Bob

Thanks Bob keep me updated if you can .
Cheers Greg
Customer: replied 3 years ago.

Hi Greg, Kia phoned yesterday and the tech department have asked that the transmission fluid is changed ,just as you said.They are going to take a sample of the oil to test regards Bob