HEMI, Auto tran sucks down gas on hyway

  • 2008 DODGE RAM
  • 37,000 MILES
Hemi, Auto tran sucks down gas on hyway. Good road and conditions, no load on truck. Set cruise at 60mph notice rpm jumping 300-400rpm, drive short distance goes up and drops down. Next condition, rpm stays at 1900-2000rpm sometimes by speeding up and backing off it will drop to 1600rpm, were it should be at 60mph. Sometimes slowing down can make it drop also. It does same without cruise control. Adding just a small load on truck seems to make situation worst were it stays at high rpm. At its highest gear ratio, lowest rpm is the torque converter surpose to lock up? May be it isnt. Is there a throttle postion senser that could effect the trany. Some time ago Dealer did some computer change that was surpose to modify shift patern. This may not have be the problem. Unfortunatly when the dealer gets the truck the problem doesnt occurr, I would have thought a scan tool would show up something. Thank you
Tuesday, January 15th, 2013 AT 9:34 PM

1 Reply

That is a tough one. If there was a problem with the converter, it would set a trouble code. Can you hear the engine changing RPM's or could it be a bad tach?
Was this
Tuesday, January 15th, 2013 AT 11:26 PM

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