[rhondella13]

Hi all! I’ve suddenly started experiencing a shudder or vibration like I’m driving over rumble strips with my 2017 LT 2.0 4cyl turbo. It happens randomly as I’m driving and I’ve done some research on it but wanted to get some opinions or thoughts. So far, I’ve heard to flush the transmission fluid 3x and if that doesn’t help then it’s time to replace the torque converter. I don’t have a mechanic near me, so I’m unsure if any could flush the transmission or if I would have to go a Chevy dealer specifically. Any help would be much appreciated! Thank you!

[arpad_m]

The solution was published by GM in 2019, it consists of flushing the transmission with the latest, properly non-hygroscopic Mobil 1 Synthetic LV ATF HP fluid that has been available approximately since March 2019.

If the torque converter clutch isn't too damaged, this will solve the problem; if not, the torque converter needs to be replaced as well. Since the car is out of warranty, I'd try not to drive it much until this is performed, because the service department will charge you a pretty sum in labor hours for the TC replacement.

The related technical service bulletin is 18-NA-355 if you want to read up on the details.

[rhondella13]

Originally Posted by arpad_m

The solution was published by GM in 2019, it consists of flushing the transmission with the latest, properly non-hygroscopic Mobil 1 Synthetic LV ATF HP fluid that has been available approximately since March 2019.

If the torque converter clutch isn't too damaged, this will solve the problem; if not, the torque converter needs to be replaced as well. Since the car is out of warranty, I'd try not to drive it much until this is performed, because the service department will charge you a pretty sum in labor hours for the TC replacement.

The related technical service bulletin is 18-NA-355 if you want to read up on the details.

Wow! Thank you so much!! I appreciate it! This helps so much

[rhondella13]

Sorry one more question! Is this something a regular shop can do or would you suggest taking it to the dealership? Thanks again!

[arpad_m]

You're welcome The procedure is basically a 100% flush to get all the absorbed water out of the transmission and torque converter, and the TSB recommends a particular machine (TransFlow), but I'm sure a well equipped shop can also do it.

Since you're out of warranty, I understand you don't want to go to the dealership, but make sure you visit a shop that is familiar with the GM 8L45 transmission you have, and uses proper equipment (so they don't simply drain the trans fluid and then refill the unit cold, for example).

[rhondella13]

Originally Posted by arpad_m

You're welcome The procedure is basically a 100% flush to get all the absorbed water out of the transmission and torque converter, and the TSB recommends a particular machine (TransFlow), but I'm sure a well equipped shop can also do it.

Since you're out of warranty, I understand you don't want to go to the dealership, but make sure you visit a shop that is familiar with the GM 8L45 transmission you have, and uses proper equipment (so they don't simply drain the trans fluid and then refill the unit cold, for example).

Thank you!! This has been so helpful!

[rhondella13]

This has got to be the most frustrating thing! Thanks GM. I’ve called several dealerships and before I even bring it in, they’re telling me I need to get a whole new torque converter, refusing to do a transmission flush. The cost is anywhere from $5k-$6k. This can’t be real life

[arpad_m]

They're ****ing with you... the torque converter is a $460 part (see here), and the fluid plus the trans filter should cost around $200.

There certainly is some labor involved, since the trans needs to be dropped for this job, but $5-6K is way too much. Keep looking, try independent mechanics and shops.

[Bumbleboy92]

The flush itself (back in 2019) was $300-$400 at the dealer, I found a dealer running a special and paid $200 for the flush on my v6. If you go the torque converter route then definitely shop independent shops pricing

[rhondella13]

Thanks everyone! I’m still shopping around but it’s not looking good unfortunately. I think the prices here are astronomical because they can smh. So far the flush around me is around $1300 ��