I have a 2011 lt1 auto, with aground 32000km. It started shifting hard between from 3rd to 4th gear, between 2500 and 3300 rpm, only while gently accelerating. If I'm givin' 'er, it's very smooth, as are all other shifts, all the time.

I brought it to the dealership almost a month ago, and I think they replaced the transmission control module and a few other sensors in the transmission (I think. That's all they told me). I know they had the transmission out of it and didn't find any issues. It's still there and was told it is still acting up.

They said they've been consulting with GM and are going to get it fixed so I'm not worried or anything like that. The service has been great, I'm in a loaner car, and everything's under warranty. I'm just curious if anyone else has experienced this issue before.

Thanks

 

Nope I haven't had this issue, glad to hear yours is under warranty

 

No work orders or invoices in CA????
In the USA we get paperwork even for warranty work.

I bet that your thermostat is broken.

 

I think Don nailed it, when they slam shifts, the thermostat is one of the "usual suspects".

 

Make sure you use an Genuine GM T-stat !!

 

are you doing about 60 km/h at that "hard" shift point? I have a chug or hard shift at that speed when its shifting to over-drive ( i guess thats what its called) You especially feel it if you are coasting around that speed and slowly hit 60 you feel it jerk

 

4th gear would be overdrive and another grab would be when the torque converter locks up

 

I haven't been back to the dealership. It's about an hour away from my house. All my info from them has been over the phone. Once it's fixed, I'll have the paperwork.

 

Yep. 60-65 km/hr-ish.

 

i think thats normal..i get that all the time in the speed range