Hard Shift from 4th to 5th gear or a bit delayed despite ATF flush and solenoids replacements

H

Husam

Joined
Apr 26, 2020
Messages
22
Location
Dubai
Gentlemen,

2015 v6 3.8L RWD Genesis: Condition:
- Mileage = About 160,000 KM.
- Location: Dubai
- Warranty: Expired
- Car very well maintained, regularly.
- All fluids changed (Engine Oil, Radiator fluid, Brake Fluid, Diff Fluid)
- All filters changed.
- ATF flushed 3 or 4 times with added ATF friction modifiers or conditioners (once added LubeGaurd Red, and another instance added BG ATC Plus with Instant Shudder Fixx).
- Zero codes in scanner; system check: OK.
- Changed all AT Shift Solenoids + Pan too.

Situation as of now:
- Hard shift or slam-like shift from 4th to 5th gear with more than gentle throttle applied ONLY after cold start. However, once the car is hot and ATF is heated up, the harsh shift at this specific gear is completely gone.

What do you guys think the best course of action is? My last resort is to pay for a full Transmission replacement which I am trying to avoid by carefully eliminating the problem.

The question is:
Why does the hard shift completely goes away after the ATF is hot. It only shifts harshly when ATF is cold (though ATF is flushed and renewed multiple times).

Let me know your thoughts.


Thanks,
Husam
 
Too many friction modifying additives. You have done enough and maybe it's time to seek the opinion of an experienced transmission person before further damage occurs.
 
It will always shift harder when cold. The quicker the shift the better really. Flaring is what to look out for or not staying in gear long enough etc.
 
Change the transmission fluid and use the approved Hyundai/KIA transmission fluid. DO NOT add any friction modifiers or other snake oil formulations to the fill. See how that works out before having any transmission repairs done.
 
It is wise to diagnose before attempting to change parts , get help from a pro.
 
MParr said:
Change the transmission fluid and use the approved Hyundai/KIA transmission fluid. DO NOT add any friction modifiers or other snake oil formulations to the fill. See how that works out before having any transmission repairs done.
Click to expand...
I already did this after the 1st flush of the ATF; I used OEM ATF yet the same behavior persisted. Even after all the flushes, I always OEM ATF.
 
Husam said:
I already did this after the 1st flush of the ATF; I used OEM ATF yet the same behavior persisted. Even after all the flushes, I always OEM ATF.
Click to expand...
Without additives? I'm not saying the additives are causing your issue, but how can we know for sure? OEM ATF should need no aftermarket additives.
 
zrxkawboy said:
Without additives? I'm not saying the additives are causing your issue, but how can we know for sure? OEM ATF should need no aftermarket additives.
Click to expand...
Yes, the first flush attempt was performed without any sort of additives. The strange behavior is only seen when ATF is cold; but once warmed up, it is smooth.
 
MParr said:
Change the transmission fluid and use the approved Hyundai/KIA transmission fluid. DO NOT add any friction modifiers or other snake oil formulations to the fill. See how that works out before having any transmission repairs done.
Click to expand...
This^
 
MParr said:
Change the transmission fluid and use the approved Hyundai/KIA transmission fluid. DO NOT add any friction modifiers or other snake oil formulations to the fill. See how that works out before having any transmission repairs done.
Click to expand...
I agree with this. Go to your Hyundai dealership and buy the Hyundai oem fluid and do a complete change. Transmissions can be finicky and that's an aspect of a car I will never experiment on.
 
Have you looked for help on a Hyundai Genesis forum? If you can’t find anything on there, then I would take it to a mechanic. This is probably more than a fluid problem.
 
Husam said:
What do you mean by "flaring"?
Click to expand...
What was wrong with it to begin with? You shouldn't do full flushes with auto transmissions just change the ATF a few times. Flare is when RPM quickly gets higher at same throttle position before auto engages/changes gear. Lubegard red wont hurt anything.
 
Husam said:
Gentlemen,

2015 v6 3.8L RWD Genesis: Condition:
- Mileage = About 160,000 KM.
- Location: Dubai
- Warranty: Expired
- Car very well maintained, regularly.
- All fluids changed (Engine Oil, Radiator fluid, Brake Fluid, Diff Fluid)
- All filters changed.
- ATF flushed 3 or 4 times with added ATF friction modifiers or conditioners (once added LubeGaurd Red, and another instance added BG ATC Plus with Instant Shudder Fixx).
- Zero codes in scanner; system check: OK.
- Changed all AT Shift Solenoids + Pan too.

Situation as of now:
- Hard shift or slam-like shift from 4th to 5th gear with more than gentle throttle applied ONLY after cold start. However, once the car is hot and ATF is heated up, the harsh shift at this specific gear is completely gone.

What do you guys think the best course of action is? My last resort is to pay for a full Transmission replacement which I am trying to avoid by carefully eliminating the problem.

The question is:
Why does the hard shift completely goes away after the ATF is hot. It only shifts harshly when ATF is cold (though ATF is flushed and renewed multiple times).

Let me know your thoughts.


Thanks,
Husam
Click to expand...
What ATF did you use? I would avoid a "Maxlife" type one size fits all universal type of fluid if that's what you used. Sorry Maxlife fans! I would get the ATF the vehicle calls for and do a fluid exchange at this point, w/o additives. If that doesn't work I'd reach out to a pro.
 
As far as additives go you chose two of the good ones IMO and they aren't causing your issues. I think its time for it to go to a transmission shop..
 
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