My 2021 GMC 3.0 diesel had a rear wheel lock up prior to its recall installation. I just got the recall done and the same day the vehicle went into limp mode. Dealer had vehicle towed to shop for valve body replacement.
is there anything I should ask the dealership to look at specifically while it is at their shop post rear wheel lock up other than just the valve body?
in addition to, should I have any additional operations done while the valve body is being replaced.
This is the first half ton with the lockup that I've heard about. For some reason I only heard about HD models. Were you towing when it happened?
@duggydo it has happened both while towing and once when trying to pass a vehicle. It was driving 55ish and then I jumped on it to pass and it locked up. I then decided to just stay behind that vehicle.
I think the dealership should end up giving you an entirely new valve body given the symptoms and issues. If they don't, something is wrong. Nate from NextGen thinks that the new valve body will have the same issue, and it's just overall bad for the transmission and driveline components.
You could try to push the dealership to upgrade the valve body with NextGens kit, however it seems hit or miss whether people are successful at convincing the dealer to do this for them. Some dealers refuse while others will install the new kit from NextGen (in a new valve body).
That being said, if GM gets you a new valve body, chances are it will get you down the road for a while, it's just hard to know if there's any residual damage to the transmission. I would want to see how bad/dark the transmission fluid is, if it's super dark then you might be down a bad path.