Tranny shifting back and forth between 3rd & 4th in Sport Mode.

[Concordium]

I was driving home today and cruising at a breezy 70-75 mph today. I tossed the car into sport mode because I was going to have a little bit of fun. However, the transmission downshifted into 5th gear.....then to 4th.....then shifted back to 5th a few seconds later.....and then back to 4th a few seconds after that. No additional throttle was being applied to the pedal during this time. I put it in normal drive mode and it functioned just fine. Swapped it back to sport mode and it kept freaking out. Manual mode works fine as well. I did a search but didn't find exactly the same problem I was having.

Car is bone stock.

[Jae]

Sport mode is weird like that...if I kick it over to sport and hit like 110-120 (4th iirc) then back off to like 50 it will stay in 3rd

Sent from my DROID RAZR HD using Tapatalk 2

[Concordium]

Yeah but I have never had that happen before. I've driven the car in sport mode many times on the freeway and it has never shifted like that. I've had it hold 4th gear at a high RPM befre but not shift back and forth like that. It just seems out of the ordinary.

[DanSVT03]

Welcome to the stock transmission tune. God awful.

[-Ray-]

Sport mode is weird like that...if I kick it over to sport and hit like 110-120 (4th iirc) then back off to like 50 it will stay in 3rd

Sent from my DROID RAZR HD using Tapatalk 2

It's designed to do that. You don't want it up shifting going around a corner unless you are on the pedal.

[BLKG8]

It's designed to do that. You don't want it up shifting going around a corner unless you are on the pedal.

Yup..
You can find a little info in your owners manual on it.

[Concordium]

Ok but I was going in a straight line between 70 & 75. It kept going back and forth between 4th & 5th every few seconds. It would downshift....stay there for a couple of seconds.....upshift and stay there for a couple of seconds. I am pretty sure the stock transmission isn't supposed to do that. Also, I have had the car for about 6 months now and have cruised with it in Sport Mode on a near daily basis and it has never done this before.

[-Ray-]

My reply was to Jae. I guess I would get my G8 at 75 with cruise control on. Put it in sport mode and expect it to drop to 5th gear. When there is no throttle input it should shift back to 6th. If it doesn't do this, I would first consider a complete fluid change if you haven't done so yet.
How many miles on the car?