2k Rpms at 70mph

[2004F250XLT]

I have a 373 rear and stock 31.5'' tires. Is this the sweet spot to be cruising on the highway? And normal for the trannie/setup Also, i got the opportunity to open it up at around 70mph, it didnt downshift, so i thought i was in the final gear, but once i hit around 87-90mph it shifted into the final gear which led me to believe that the trans is only in 4th gear at 70mph/2k rpms crusing?

[cartmanea]

I doubt it shifted at 87-90 unless you had it floored and that's when the TC finally locked up. 2k rpm is pushing it for cruising, you'll see better mileage in the 1800-1900 range. Under very light throttle it should be in OD with the TC locked by about 50 mph.

[atvrider93]

ya if you layed into it your TC probably unlocked and then locked back around 90.