Transmission Flare

[clinebarger]

Good point. Didn't observe any flare this past winter when it was the coldest it had been since the fluid was changed last February 25th.

Since I'm not observing any flare, and haven't for a while, do you think it's worthwhile to have the level checked just to be sure, or perhaps just not do anything until or if it happens again?

Having it checked sure would give me peace of mind, But it's not my vehicle & would hate for you to waste money if it was in fact filled correctly.

I see you're in San Francisco? If you drive up some of those grades without the unit sucking air.....It's likely not to terribly underfilled. We have some 100% Grades in my neighborhood & can usually spot a underfilled unit going up one. Diagnoses Allison 1000's with a dropped sump filter everytime!

 

[haggler]

I get this flare on my 2018 kia optima when the car has sat over night shifting and only 2-3 on soft throttle. Ambient temps do seem to make a difference. I changed the fluid at 30k and it did it before with factory fluid. I initially thought it was the change to max life atf. I thought it was under filled but I added another 3/4 quart and did a level check at temp and it was definitely topped off. It has to be a computer controlled issue, I've never have the issue when I manually shift.

 

[Shel_B]

Having it checked sure would give me peace of mind, But it's not my vehicle & would hate for you to waste money if it was in fact filled correctly.

I see you're in San Francisco? If you drive up some of those grades without the unit sucking air.....It's likely not to terribly underfilled. We have some 100% Grades in my neighborhood & can usually spot a underfilled unit going up one. Diagnoses Allison 1000's with a dropped sump filter everytime!

I'm not in SF but nearby. There is one hill I go up several times a week. It's fairly steep and the car is usually cold, starting from being parked overnight. Point to point distance is 2.3 miles and the hill starts at mile 1.8. Haven't experienced flare in those circumstances.

 

[clinebarger]

I get this flare on my 2018 kia optima when the car has sat over night shifting and only 2-3 on soft throttle. Ambient temps do seem to make a difference. I changed the fluid at 30k and it did it before with factory fluid. I initially thought it was the change to max life atf. I thought it was under filled but I added another 3/4 quart and did a level check at temp and it was definitely topped off. It has to be a computer controlled issue, I've never have the issue when I manually shift.

There are many units now that employ Low Pressure Priming Circuits to combat symptoms like this. Manually shifting can bring on Underdrive/Overrun members that just mask the symptom.

 

[clinebarger]

I'm not in SF but nearby. There is one hill I go up several times a week. It's fairly steep and the car is usually cold, starting from being parked overnight. Point to point distance is 2.3 miles and the hill starts at mile 1.8. Haven't experienced flare in those circumstances.

If a underfilled unit was to act up....It will be on a steep grade while cold!

 

[haggler]

There are many units now that employ Low Pressure Priming Circuits to combat symptoms like this. Manually shifting can bring on Underdrive/Overrun members that just mask the symptom.

So if I understand correctly, the thicker atf is not providing enough preliminary pressure? From what I understand this trans has been around for quite a while so maybe it's not the latest and greatest, but if there's a way to fix this I'm inclined to try. I don't think it's really hurting anything though. Lots of similar complaints on the forums. I recently had them update my TCU software which fixed a rough 2-1 per tsb, but no fix here. I found another thread that talks about the difference fluid characteristics at various temps.
https://www.hyundai-forums.com/threads/2nd-to-3rd-rough-gear-shift.247938/post-2145106

 

[clinebarger]

Initial Clutch Priming issues can't always be fixed with calibration changes, As in....It's already best it will ever be with any "mass release" update.

 

[64bawagon]

The fluid temp is stable at just under 200 degrees. This thing has a huge radiator and trans cooler, fluid temp is not the issue.

 

[CKN]

Probably getting the fluid too hot and thinning it out, you should probably manually shift when towing and stay out of top gears and especially overdrive.

The fluid (Dex 6) can take 265 degrees. if it's a half-ton with the 6 or 8 speed. Almost impossible to over heat in a normal operating truck.