[Lemon SS]

Hi all ,

I'm new here & a new camaro owner & coupe cars in general. So recently I bought a camaro 2018 auto transmission (14k mile)

I have noticed the shudder happens from 40mil & up to 80 mil. The way it happens is that it only occurs when cruising especially when the engine is switching to 4V and it goes away when accelerating. Also noticed that it becomes smooth when driving above 85 mil.

Took the car to a dealership & said it they'll not fix it because it was an import car. So they won't fix it unless I sign a waiver in case they break something. So obviously I refused & I plan to take it to a trusted workshop.

So my questions are, what are your suggestions to solve the issue. What steps should I take & what type of trans oil should I use? If anybody succeeded in solving the issue, please share. Your support would be appreciated.

Thanks in advance all.

[rcoe]

First thing do a complete flush using Mobile1 synthetic AFT LV HD. The important part is the LV for low viscosity. It will take quite a bit of fluid to flush the old stuff out, easily over 20qts.

Tuning can also help.

All else fails replace the converter.

[FlukeSS]

Originally Posted by rcoe

First thing do a complete flush using Mobile1 synthetic AFT LV HD. The important part is the LV for low viscosity. It will take quite a bit of fluid to flush the old stuff out, easily over 20qts.

Tuning can also help.

All else fails replace the converter.

They usually do this 3 times, so 30 qts total, then fill and drive for a while, if you still get the shudder, your torque converter is shot, and needs to be replaced... BEFORE it damages the transmission.

[Cyrus]

Originally Posted by FlukeSS

They usually do this 3 times, so 30 qts total, then fill and drive for a while, if you still get the shudder, your torque converter is shot, and needs to be replaced... BEFORE it damages the transmission.

I believe the newest TSB only requires 1 flush. Originally it was 3 flushes.

[Lemon SS]

I see, thank you all for the help. Will try this weekend to find the oil & do the needed. hopefully it goes away.

[arpad_m]

Hey Lemon, this is the official procedure that a US dealer would follow: https://static.nhtsa.gov/odi/tsbs/20...63890-9999.pdf. The transmission fluid you want is called Mobil 1 Synthetic LV ATF HP, part number 19417577 in GM's system.

It's a single flush process with a purpose built flush machine (as Cyrus says, the triple flush was an older attempt at removing the previous, even worse fluid, but the latest 2019 fluid supersedes them all, actually works and no longer requires the triple flush).

Not sure what equipment other shops will have, but even if they don't have an equivalent flush machine, you should go and get it done right now, expunging "only" 99% or even 95% of the old fluid will still be highly relevant. If the shudder returns after the flush, unfortunately you'll need a new torque converter, GM part number 24290214.

Getting a transmission tune is also advised, although not required, to extract maximum performance out of your 8L90 and to make 101% sure the shudder never returns. Plenty of remote tuning options even here in the forums, my tune is from Ted Jannetty at jannettyracing.com, and it's spot on (I have the same 2018 with the same trans as yours).

[Lemon SS]

Originally Posted by arpad_m

Hey Lemon, this is the official procedure that a US dealer would follow: https://static.nhtsa.gov/odi/tsbs/20...63890-9999.pdf. The transmission fluid you want is called Mobil 1 Synthetic LV ATF HP, part number 19417577 in GM's system.

It's a single flush process with a purpose built flush machine (as Cyrus says, the triple flush was an older attempt at removing the previous, even worse fluid, but the latest 2019 fluid supersedes them all, actually works and no longer requires the triple flush).

Not sure what equipment other shops will have, but even if they don't have an equivalent flush machine, you should go and get it done right now, expunging "only" 99% or even 95% of the old fluid will still be highly relevant. If the shudder returns after the flush, unfortunately you'll need a new torque converter, GM part number 24290214.

Getting a transmission tune is also advised, although not required, to extract maximum performance out of your 8L90 and to make 101% sure the shudder never returns. Plenty of remote tuning options even here in the forums, my tune is from Ted Jannetty at jannettyracing.com, and it's spot on (I have the same 2018 with the same trans as yours).

Thanks Aprad for the procedure, I'll show it to the mechanic.

I'll report back the results.

[ctrlz]

Here's one of the original tech bulletins. the correct term is hygroscopic, not hydroscopic. The clutch slip shudder is exacerbated by the AFM in V4 mode, which has a built-in slip of 10 rpm.
https://gm-techlink.com/?p=11127

[Lemon SS]

A quick update.

Just finished the flushing 2 ago & the issue is gone��. I'm driving the car for work & long commute to make sure the issue is really solved.

Thank you all for the support. Really appreciate it.

[Bumbleboy92]

Originally Posted by Lemon SS

A quick update.

Just finished the flushing 2 ago & the issue is gone��. I'm driving the car for work & long commute to make sure the issue is really solved.

Thank you all for the support. Really appreciate it.

Keep an ear out for it, my transmission flush worked but only lasted a little under a year (10k miles). Then it returned and I had the car tuned with AFM turned off and hadn’t had the shudder issue again

[Lemon SS]

Originally Posted by Bumbleboy92

Keep an ear out for it, my transmission flush worked but only lasted a little under a year (10k miles). Then it returned and I had the car tuned with AFM turned off and hadn’t had the shudder issue again

Will do. Hopefully it doesn't comes back.

Thank you all again for the support.

[Spaceme1117]

Originally Posted by Lemon SS

A quick update.

Just finished the flushing 2 ago & the issue is gone��. I'm driving the car for work & long commute to make sure the issue is really solved.

Thank you all for the support. Really appreciate it.

Excellent.

I bought my 2017 used a couple of years ago. I did a flush myself and glad I did as the trans was 2 quarts low. I think a dealership flush was done but they didn't do the refill properly (run up to temp and get level correct with car running).

Also, had a TSB done for a software error on 2017 cars. This fixed the error and smoothed out the harsh 1st shift on cold fluid.

[Kainzo]

How much is a transmission flush for a 2017 camaro anyways?

[Cyrus]

Originally Posted by Kainzo

How much is a transmission flush for a 2017 camaro anyways?

In Canada around $1,000 at a GM dealer. Thats what I paid 15 months ago and I shopped around. And all they did was swap out the fluid once, not three times. I guess the cost of the fluid is outrageous.