[Ken1]

I decided to start a new thread because this title describe the problem.

My wife's new Malibu will less than 1K miles acts as if it has a weak exhaust brake.

This morning in my test drive: At the crest of a long downhill run I release the gas pedal @70 MPH. During the trip down hill you could feel the trans engaged, and @ 45 +/- MPH you could feel the trans downshift and a jump in RPM. All this with no pressure on gas pedal or brake. I repeated this on the road test twice.

My concern is wear on trans and added heat to ATF.

Ken

 

[BillD64]

At 70 mph the tran is in 6th gear. At 45 mph the engine would be turning to slow in 6th so the trans shifts to 5th to protect the engine and to give quicker response if you step on the gas.

Bill

 

[Macleod52]

Sounds normal to me. The 6spd is a different beast than the 4spd, so the shifting will be different.

 

[bballr4567]

Yup its all normal. Ours does the exact same thing. If you want to learn what MPH the trans will shift at go into manual mode and speed up really slow while trying to upshift into each gear.

 

[Ken1]

Thanks
Ken

 

[USA1fan]

All normal for the six speeds. Keep in mind that GM's press releases about these transmissions also mention something about grade logic, something I'm sure I'm fairly safe saying isn't in any of the GM four speeds I've owned.