Overdrive Shift speed

[MrLucky]

At what speed should overdrive kick in, a friend has a 2003 Duramax and overdrive shifts at 42 MPH, mine a 2004 Duramax shifts at 47 MPH, I'm Sure this has a toll on MPG, Especially if you drive around town at 45 MPH

[RdTxTd]

Are you sure that's not the TC locking up at 47? My 2005 hits OD at about 40-42, then locks the TC at about 47. Get up to about a steady 44 MPH then lock out overdrive. If it downshifts, you were already in OD.

Dave

[MrLucky]

Thanks Dave checked out your suggestion and your right

Dave