Serious Transmission Jerking/Knocking noise when accelerating

[rmod]

I want to keep this car until it actually dies (or requires mechanical work exceeding the value of the car) but I cannot drive a car with a transmission like this for another 77k. It's really disappointing. The manual said not to change the fluid, the dealer said i should have, and clearly i should have. Now i possibly messed something up long term, and the only solution i see here is for someone to take apart the trans and see what's wrong in there. Idk what to do.

Just do a couple of more drain and fills yourself and see if that solves / minimizes the issue that you have. Perhaps you can try some other brands like Amsoil, Ravenol or Valvoline for your transmission fluid.
This is a procedure for "TCM Relearn" once the adaptive values are reset. Maybe you can try this after a reset.
("APS" below means your accelerator input, "SBW"= Shift By Wire)

 

[thatjawncrazy]

Sure, i could buy trans fluid, drain and fill several times, worry about messing up the levels/programming, reprogram it myself by doing this very specific procedure, or my car could just not have this issue.

Time is what i value above everything else. I've already spent the money having it diagnosed - and it still happens. Rather not tackle major transmission service on my own as well. I do all my own work...but transmission and suspension are two things i'd rather leave to the professionals.

Side note, pretty sure my coilover should not be aligned this way. I don't see evidence that the sway bar link hits the driveshaft and causes "knocking", especially since it only happens once per tire rotation.

Either way...clearly the shop that did mine were not professionals

 

[pulsar]

Appears you have aftermarket shocks installed. Were they direct replacements for the OEM’s? The sway bar attachment to the shock area certainly does not look right and the CV shaft being that close surely was not that way when stock? Is this an install problem that can be corrected or if using those adjustable shocks what you see is the best it’s gonna be? Never paid that close attention to my sway bar mounts for my stock electronic shocks to really be of much help until my next oil change and I’m under the car again.

 

[JCtx]

If you were the original owner, you'd still be under the 10-yr/100K-mile power-train warranty, so that tells me you bought the car used, no? If yes, that means the previous owner could have abused the car in numerous ways that you never knew about, so it might have nothing to do with you. But that's the risk you take buying used vehicles. If the issue is not too obvious now, you might be better off parting ways with the car now. Or if you want to keep it, just get the transmission checked by a specialty shop, and go from there. If it needs fixing, it'd be done right. Good luck.

 

[DAYTA]

I was afraid to touch my transmission lol. Like volfy said, might have been easy, but i'll leave this one to someone else...

They charged $579 for a full flush and resetting the adaptive values. This was $208 for parts and $320 for labor, that's all i know.

For the resetting of the adaptive values, does this require a Hyundai/Genesis-specific module that only dealerships have access to? Or can this be performed by an indy tech as well?

I'm at just under 41k miles and I'm thinking about preemptively doing a trans flush. However, I would MUCH prefer to use my indy tech that I trust instead of going to a dealership...

 

[Volfy]

If all you doing is ATF drain and refill, there is no need to reset the TCM adaptive relearn. It isn't mentioned in the factory service manual procedure. https://www.kstinger.com/oil_filter-509.html Nor does it make practical sense for a simple fluid change.

 

[thatjawncrazy]

HKS M45iL plugs came in today. Gotta change them out and see if my issue is fixed.

 

[thatjawncrazy]

My "transmission issues" were not trans issues, it was a misfire. Whatever plugs the Genesis dealer put in at 42k, they started cutting out another 38k miles later. The manual says OEM plugs need replacing at 42k, but maybe the Genny dealer installed plugs that were not OEM. I don't blame anyone! False alarm!

Either way, I'm now running HKS M45iL plugs. I didn't see this written anywhere, so let it be known - you can run these plugs with no JB4 just fine. Issue fixed.

The middle passenger side plug & coil is totally doable without removing the intake manifold. Unbolt it, flip it 180º, snake it out towards the front of the car.

 

[Volfy]

Glad you finally got it sorted out. There were no OBD2 fault code(s) for misfiring?

Yeah, FWIW, it's yet more validation to DIY, so you know EXACTLY what goes into your own car.

 

[thatjawncrazy]

Glad you finally got it sorted out. There were no OBD2 fault code(s) for misfiring?

Yeah, FWIW, it's yet more validation to DIY, so you know EXACTLY what goes into your own car.

No fault codes, but I DID have it go into limp mode once, which happened to be literally on the way into my first day of work at my new job. I shut it off, restarted, and it never happened again. That was about 5k miles ago.

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[pulsar]

No fault codes, but I DID have it go into limp mode once, which happened to be literally on the way into my first day of work at my new job. I shut it off, restarted, and it never happened again. That was about 5k miles ago.

Odd no codes but maybe the misfire was so intermittent the OBDII did not have time to set a code yet? I’ve seen some misfire codes in other vehicles and figuring out the exact cause is not easy for it could be coil or plug related? Plugs being the cheapest thing to try first. Glad you seem to have the issue behind you.

 

[thatjawncrazy]

The issue came back again. No joke. Did another few hundred miles on these plugs and the same exact issue came back while I was in New Hampshire. It got pretty bad.

I do know that the issue happens MORE when the car is in "custom" mode when I have the AWD set to "sport" which I believe sends more power to the rear. I have no idea how that helps me, but at this point, I want to bring it to a dealer and drive a technician around and ask them to consider whether it's the torque converter. I don't know what else it could be....

Even more infuriatingly, the issue is still INTERMITTENT. Some drives it happens, sometimes it doesn't.

 

[5.0KDM]

The issue came back again. No joke. Did another few hundred miles on these plugs and the same exact issue came back while I was in New Hampshire. It got pretty bad.

I do know that the issue happens MORE when the car is in "custom" mode when I have the AWD set to "sport" which I believe sends more power to the rear. I have no idea how that helps me, but at this point, I want to bring it to a dealer and drive a technician around and ask them to consider whether it's the torque converter. I don't know what else it could be....

Even more infuriatingly, the issue is still INTERMITTENT. Some drives it happens, sometimes it doesn't.

bad coil pack?

 

[thatjawncrazy]

bad coil pack?

no idea - how can i test it? and why does it only happen at lower speeds? cruising at steady rpm, or when accellerating at higher speeds, it's just fine. seems like a bad plug or bad coil pack would've been an "always bad" issue if that makes sense

 

[5.0KDM]

no idea - how can i test it? and why does it only happen at lower speeds? cruising at steady rpm, or when accellerating at higher speeds, it's just fine. seems like a bad plug or bad coil pack would've been an "always bad" issue if that makes sense

Remove them and check the insides or the body of it for tears. It does make sense it would be always bad but it might be a small tear that might arc. It is strange tho. I'm just shooting out ideas.

 

[thatjawncrazy]

Tough week for this car. Took it into the dealer for the issues in this thread. Turns out my left motor mount was so loose they could see the engine moving back and forth - I've never heard of that issue before. The knocking noise was a front axle, and the sound switched from the right side to the left side after they fixed the motor mount.

They suggested I replace both axles, which I'm doing just to be safe. The noise only happens when the front end lifts up enough for the axles to no longer be parallel to the ground. The axles don't move back and forth or move around when I try to move them with my hand.

My car has been at least 1.4 inches lower than stock height for the past 65,000 miles, not sure if that has something to do with it.

Btw, the "jerking" when i let off the gas at low speeds was the engine shifting. Now that my motor mounts are tight, it doesn't do that!

So, I spent no money on this car outside of maintenance and mods for 85,000 miles! Pretty good! But the streak is broken. The engine is super smooth now at least...

 

[Seeing_Red]

If you do a "flush" at home its not really a flush. At home you can basically do 4qts at a time. Drain 4, fill 4. Start car shift through gears and doit again. Ive done it at home and its a little bit of a process.

However, after doing it and flushing until nice clean flud was coming out, the trans temps, shifts etc are sooooo much better. I replaced with Motul.

Hey man sorry to reply to an ancient thread but was the Motul fluid you used the ATF VI? Any reason you chose them over something like Amsoil?

Also, have you replaced differential fluid with a Motul product?

I'm looking to do a transmission fluid change now, not due to any issues but my car has 40k miles and at least 15k of those have been "harsh" with ECU and TCU tuned.

Appreciate the help! Tried searching the forum and I was having trouble finding confirmation of the exact fluid.

 

[Cashby]

Hey man sorry to reply to an ancient thread but was the Motul fluid you used the ATF VI? Any reason you chose them over something like Amsoil?

Also, have you replaced differential fluid with a Motul product?

I'm looking to do a transmission fluid change now, not due to any issues but my car has 40k miles and at least 15k of those have been "harsh" with ECU and TCU tuned.

Appreciate the help! Tried searching the forum and I was having trouble finding confirmation of the exact fluid.

Motul or Amsoil works fine. I even did one with Valvoline Maxlife and it worked just as well.

Diff fluid I used Amsoil 75w90