Transmission issue

[joschneider]

I've felt a hard downshift more than a couple of times. It's more evident when coasting and I have to apply the brakes. Sometimes is on the contrary, when coasting at highway speeds and I suddenly need to apply the gas pedal the tranny jerks when upshifts. It's as if the tranny doesn't engage the correct speed for the actual RPM.

Right, but if some people are saying they’ve never felt this... I wonder if it’s a difference of feeling or an actual difference

 

[Cgo]

Other than maybe a thermostat, can’t imagine anything being internal to the transmission cooler? If over temp related, seems the ECU would pick up on that and throw an engine code? Under normal driving can’t figure the transmission getting all that hot? I read somewhere our engines have an electronic thermostat fully controlled by the ECU and not a conventional one that is heat controlled with no computer. Not sure if the transmission cooler lines and the engine coolant hoses all see the same temps and are tied together, or independently controlled somehow?

Afyer some research on the interweb, it seems as though the internal core is cracking at the seams of the tubes inside the cooler allowing the coolant and oil to mix creating a sludge that eventually clogs things up within the transmission and even the engine internals where the shared coolant passes through the jackets. It makes a real mess apparently.

 

[danygenesis]

Right, but if some people are saying they’ve never felt this... I wonder if it’s a difference of feeling or an actual difference

This is very subjective, the only way to get the real answer is to have the same car being driven by two different drivers or vice versa, two different cars driven by just one driver.

 

[Toddasaurus]

You’ve never had it hard shift during a downshift? A feeling like it didn’t quite match rpms to be smooth and it results in a jerk as you’re braking or coasting down?

Nope. Despite the subjectivity of this, I really feel like my tranny has always downshifted very smoothly and calmly. I've not once felt it jerk, or shift hard, not at all.

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[Husky]

Is this a water cooled transmission oil cooler? All the oil coolers I've seen were air cooled, like a normal radiator.

 

[pulsar]

Afyer some research on the interweb, it seems as though the internal core is cracking at the seams of the tubes inside the cooler allowing the coolant and oil to mix creating a sludge that eventually clogs things up within the transmission and even the engine internals where the shared coolant passes through the jackets. It makes a real mess apparently.

Not good at all. I have not poked around under the hood yet to see if we have a transmission dip stick or not? If a contamination gets in the transmission fluid if would show up on the dip stick. A external tranny cooler would have mitigated co-mingling of fluids vs borrowing from the engine radiator. Newer cars these days seem to not have ways to even re-fill tranny fluid for manufacturers don’t won’t us touching the tranny.

 

[Toddasaurus]

Is this a water cooled transmission oil cooler? All the oil coolers I've seen were air cooled, like a normal radiator.

This is our transmission cooler.



I was under the impression that only ATF flows through there. *shrug*


EDIT: Here's straight from the FSM.... Notice at the very bottom it states to refill with ATF.

 

[elsid88]

Dec '18 build bought Sport Edition 3.3(awd) in July 2019, 3500k - certainly can feel the downshifts but wouldn't say they are jerky, but are noticeable. Aware of it more when driving in ECO mode vs. SPORT or COMFORT.

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[Toddasaurus]

The engine oil cooler, on the other hand, is a water-to-oil separator. It's that block that the oil filter attaches to. It is object A in the bottom picture of this page from the FSM...



It is the metal portion that the oil filter housing attaches to. This is where oil and coolant equalize temperature relative to each other. These types of coolers can definitely fail, at least in older cars I've worked on. But if this thing is failing I doubt you'd have shifting problems...

 

[KptKrunch]

Have a little over 3k miles on my 3.3T. Two days ago while coming up to a stop sign in my neighborhood, I let it coast slowly and wasn't going to use the brakes until I needed to. I couldn't tell if it was 3rd to 2nd or 2nd to 1st gear but it was a real hard downshift that jerked me forward pretty good. I then proceeded to drive around the block and tried to duplicate it, it did it once more. I drove around the block and tried several more times after that and it didn't happen anymore. First time this has ever happened since buying the car in July 2019. Also, I did have it in Sport mode.

*Dec 2018 build date

I've felt a hard downshift more than a couple of times. It's more evident when coasting and I have to apply the brakes. Sometimes is on the contrary, when coasting at highway speeds and I suddenly need to apply the gas pedal the tranny jerks when upshifts. It's as if the tranny doesn't engage the correct speed for the actual RPM.

Dec '18 build bought Sport Edition 3.3(awd) in July 2019, 3500k - certainly can feel the downshifts but wouldn't say they are jerky, but are noticeable. Aware of it more when driving in ECO mode vs. SPORT or COMFORT.

To Elsi point, this is what I'm curious about. What mode are you guys in? I'm currently exclusivley running sport mode during the engine break in and using my paddle shifters quite a bit and the tranny has been fine. I only have a little over 500kms on it though (only have had the car for less than two weeks so not much driving).

Would be interesting to hear what modes are causing this, and if custom mode than what are the settings.

 

[danygenesis]

3.3T Prestige, Smart mode almost all the time.

 

[joschneider]

Sport 90% of the time, comfort the rest for me

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